,transcrib]'s ,notes ,text betwe5 und]scores1 equal signs & tildes repres5ts text pr9t$ 9 italics1 bold face & sans-s]if1 respectively4 ,small capitals h be5 replac$ ) ,,all ,,capitals4 ,m ,transcrib]'s ,notes may be f\nd at ! end ( ?is text4 ,,tunnel+3 ,a ,,practical ,,treatise ,,by ,,*>les ,,prel9i1 ,c4 ,e4 ,,au?or ,,( 8,,e>? ,,& ,,rock ,,excavation10 8,,dr$ges ,,& ,,dr$g+10 8,,e>? ,,slopes1 ,,reta9+ ,,walls ,,& ,,dams10 ,,etc4 ,,pr(essor ,,( ,,civil ,,eng9e]+ ,,9 ,,manhattan ,,college1 ,,new ,,york #afg ,,illu/rations ,,six? ,,edition1 ,,revis$ ,,& ,,enl>g$ ,illu/ration ,,new ,,york ,d4 ,,van ,,no/r& ,,company ,,tw5ty-,,five ,,p>k ,,place #aiab ,,copyright1 #aiab1 ,,by ,d4 ,,van ,,no/r& ,,company ,,new ,,york ,/anhope ,press ,f4 ,h4 ,,gilson ,,company ,,bo/on1 ,u4,s4,a4 ,,preface ,,to ,,! ,,six? ,,edition ,dur+ ! few ye>s t h elaps$ s9ce ! publication ( ! fir/ edition ( ?is "w1 ! art ( tunnel+ ?r\gh diff]5t soils & especially "u l>ge bodies ( wat]1 has made consid]able progress4 ,dur+ ! la/ t5 ye>s1 no less ?an eight subaque\s tunnels involv+ ! con/ruction ( sixte5 tubes h be5 con/ruct$ = ! s]vice ( ! city ( ,new ,york alone4 ,! read] w1 no d\bt1 also recall ! tunnels "u ! ,bo/on ,h>bor1 ! ,/4 ,clair1 ! ,*>les & ,detroit ,riv]s 9 our own c\ntry z well z ! tunnels "u ! ,?ames & ! ,se9e 9 ,europe4 ,eng9e]s1 contractors & workm5 h acquir$ su* exp]i5ce 9 ^! difficult und]gr\nd & "u-riv] con/ruction t ! "w is n[ und]tak5 )\t any ( ! fe> & hesitation t 7 associat$ ) ! e>li] ent]prises4 ,z entirely new me?ods h be5 introduc$ by pr(essional m51 x 0 f\nd necess>y to arrange ! pres5tation ( ! subject 9 ?is six? edition s z to give due prom95ce to ^! rec5t me?ods4 ,besides ?is1 o!r *anges h be5 made 9 ord] to give great] att5tion to ,am]ican me?od ( excavat+ tunnels ?r\gh rock & loose soil4 ,?is w expla9 ! treatm5t ( ! cr[n-b> & also ! ext5sive illu/ration ( ! head+ & b5* me?od z well z ! drift me?od ( driv+ tunnels :i* is foll[$ 9 ! ,unit$ ,/ates4 ,space has also be5 giv5 to important tunnels rec5tly built ma9ly = ! purpose ( illu/rat+ ! v>i\s me?ods discuss$ 9 ! text & also to br+ out m cle>ly ! *>act]i/ics ( ! diff]5t me?ods ( tunnel excavation4 ,! au?or hopes t ^! add$ features w meet ! pres5t requirem5ts ( eng9e]s & /ud5ts4 ,,*>les ,,prel9i4 ,,manhattan ,,college1 ,,new ,,york ,,city4 ,,cont5ts ,,page ,,introductory--,,! ,,hi/orical ,,developm5t ,,( ,,tunnel ,,build+ xiii ,,*apt] ,i4 ,,prelim9>y ,,consid]ations2 ,,*oice ,,betwe5 ,a ,,tunnel ,,& ,,an ,,op5 ,,cut2 ,,geological ,,surveys #a ,,ii4 ,,me?ods ,,( ,,det]m9+ ,,! ,,c5t] ,,l9e ,,& ,,=ms ,,& ,,dim5sions ,,( ,,cross-,,section #i ,,iii4 ,,excavat+ ,,ma*9es ,,& ,,rock ,,drills2 ,,explosives ,,& ,,bla/+ #bb ,,iv4 ,,g5]al ,,me?ods ,,( ,,excavation2 ,,%afts2 ,,classification ,,( ,,tunnels #cf ,v4 ,,me?ods ,,( ,,timb]+ ,,or ,,/rutt+ ,,tunnels #dg ,,vi4 ,,me?ods ,,( ,,haul+ ,,9 ,,tunnels #ei ,,vii4 ,,types ,,( ,,c5t]s ,,& ,,molds ,,employ$ ,,9 ,,con/ruct+ ,,tunnel ,,l9+s ,,( ,,masonry #ff ,,viii4 ,,me?ods ,,( ,,l9+ ,,tunnels #gb ,,ix4 ,,tunnels ,,?r\gh ,,h>d ,,rock2 ,,g5]al ,,discussion2 ,,repres5tative ,,me*anical ,,in/allations ,,= ,,tunnel ,,"w #hd ,x4 ,,tunnels ,,?r\gh ,,h>d ,,rock 7cont9u$72 ,,excavation ,,by ,,drifts2 ,,! ,,simplon ,,& ,,murray ,,hill ,,tunnels #ajb ,,xi4 ,,tunnels ,,?r\gh ,,h>d ,,rock 7cont9u$72 ,,excavation ,,by ,,head+s #acj ,,xii4 ,,excavat+ ,,tunnels ,,?r\gh ,,s(t ,,gr\nd2 ,,g5]al ,,discussion2 ,,! ,,belgian ,,me?od #adc ,,xiii4 ,,! ,,g]man ,,me?od--,,excavat+ ,,tunnels ,,?r\gh ,,s(t ,,gr\nd 7cont9u$72 ,,baltimore ,,belt ,,l9e ,,tunnel #aee ,,xiv4 ,,! ,,full ,,section ,,me?od ,,( ,,tunnel+2 ,,engli% ,,me?od2 ,,am]ican ,,me?od2 ,,au/rian ,,me?od #aff ,,xv4 ,,special ,,trea*]\s ,,gr\nd ,,me?od2 ,,italian ,,me?od2 ,,quicks& ,,tunnel+2 ,,pilot ,,me?od #ahb ,,xvi4 ,,op5-,,cut ,,tunnel+ ,,me?ods2 ,,tunnels ,,"u ,,city ,,/reets2 ,,bo/on ,,subway ,,& ,,new ,,york ,,rapid ,,transit #aie ,,xvii4 ,,subm>9e ,,tunnel+2 ,,g5]al ,,discussion2 ,,! ,,sev]n ,,tunnel #bah ,,xviii4 ,,subm>9e ,,tunnel+ 7cont9u$72 ,,! ,,compress$ ,,air ,,me?od2 ,,! ,,milwaukee ,,wat]-,,works ,,tunnel #bbe ,,xix4 ,,subm>9e ,,tunnel+ 7cont9u$72 ,,! ,,%ield ,,sy/em #bch ,,xx4 ,,subm>9e ,,tunnel+ 7cont9u$72 ,,! ,,%ield ,,& ,,compress$ ,,air ,,me?od2 ,,! ,,hudson ,,riv] ,,tunnel ,,( ,,! ,,p5nsylvania ,,railroad #bfc ,,xxi4 ,,subm>9e ,,tunnel+ 7cont9u$72 ,,tunnels ,,at ,,v ,,%all[ ,,dep?2 ,,! ,,c(f]dam ,,me?od2 ,,! ,,pneumatic ,,caisson ,,me?od2 ,,! ,,jo9+ ,,toge!r ,,sections ,,( ,,tunnels ,,built ,,on ,,l& #bha ,,xxii4 ,,accid5ts ,,& ,,repairs ,,9 ,,tunnels ,,dur+ ,,& ,,aft] ,,con/ruction #cja ,,xxiii4 ,,rel9+ ,,timb]-,,l9$ ,,tunnels ,,) ,,masonry #cae ,,xxiv4 ,,! ,,v5tilation ,,& ,,light+ ,,( ,,tunnels ,,dur+ ,,con/ruction #cbe ,,xxv4 ,,! ,,co/ ,,( ,,tunnel ,,excavation ,,& ,,! ,,"t ,,requir$ ,,= ,,"w #ccf ,,li/ ,,( ,,illu/rations ,,figure ,,page #a4 ,diagram ,%[+ ,mann] ( ,l9+ 9 ,rectil9e> ,tunnels #aj #b4 ,b4 ,r4 ,value's ,device = ,locat+ ! ,c5t] ,l9e ,inside ( a ,tunnel #aa #c4 ,triangulation ,sy/em = ,e/abli%+ ! ,c5t] ,l9e ( ! ,/4 ,go?>d ,tunnel #ab #d4 ,me?od ( ,transf]r+ ! ,c5t] ,l9e d[n ,c5t] ,%afts #ac #e4 ,me?od ( ,transf]r+ ! ,c5t] ,l9e d[n ! ,side ,%afts #ad #f4 ,me?od ( ,lay+ out ! ,c5t] ,l9e ( ,curvil9e> ,tunnels #ae #g4 ,diagram ( ,polyc5tric ,sectional ,pr(ile #ai #h1 #i & #aj4 ,typical ,sectional ,pr(iles = ,tunnel #bj #aa4 ,s(t ,gr\nd ,bucket ,excavat+ ,ma*9e2 ,c5tral ,london ,und]gr\nd ,railway #bb #ab4 ,column ,m\nt+ = ,p]cussion ,drill2 ,+]soll ,s>g5t ,drill ,co4 #bf #ac4 ,sket* ( ,diamond ,drill ,bit #bg #ad4 ,diagram ,%[+ ,sequ5ce ( ,excavation = ,/4 ,go?>d ,tunnel #cf #ae4 ,diagram ,%[+ ,mann] ( ,det]m9+ ,correspond5ce ( ,excavation to ,sectional ,pr(ile #ch #af4 ,pol> ,protractor = ,det]m9+ ,pr(ile ( ,excavat$ ,cross- ,section #ci #ag4 ,jo9+ ,tunnel ,/ruts by ,halv+ #dh #ah4 ,r\nd ,timb] ,po/ & ,cap ,be>+ #dh #ai4 ,ceil+ ,/rutt+ = ,tunnel ,ro(s #di #bj4 ,ceil+ ,/rutt+ ) ,side ,po/ ,supports #di #ba4 ,sill1 ,side ,po/ & ,cap ,cross ,frame ,/rutt+ #di #bb4 ,re9=c$ ,cross ,frame ,/rutt+ = ,trea*]\s ,mat]ials #di #bc4 ,longitud9al ,pol+-,bo>d ,sy/em ( ,ro( ,/rutt+ #ej #bd4 ,transv]se ,pol+-,bo>d ,sy/em ( ,ro( ,/rutt+ #ej #be4 ,%aft ) ,s+le ,transv]se ,/rutt+ #eb #bf4 ,rectangul> ,frame ,/rutt+ = ,%afts #ec #bg4 ,re9=c$ ,rectangul> ,frame ,/rutt+ = ,%afts 9 ,trea*]\s ,mat]ials #ec #bh4 ,/rutt+ ( ,timb] ,po/s & ,railway ,rail ,caps #ef #bi4 ,/rutt+ ,made ,entirely ( ,railway ,rails #ef #cj4 ,rziha's ,comb9$ ,/rutt+ & ,c5t]+ ( ,ca/ ,iron #eg #ca4 ,ca/-,iron ,segm5t ( ,rziha's ,/rutt+ & ,c5t]+ #eg #cb4 ,ca/-,iron ,segm5tal ,/rutt+ = ,%afts #eh #cc4 ,plat=m ,c> = ,tunnel ,"w #ei #cd4 ,iron ,dump-,c> = ,tunnel ,"w #fj #ce4 ,wood5 ,dump-,c> = ,tunnel ,"w #fj #cf4 ,box-,c> = ,tunnel ,"w #fa #cg4 ,elevator ,c> = ,tunnel ,%afts #fe #ch4 ,gr\nd ,mold = ,con/ruct+ ,tunnel ,inv]t ,masonry #fg #ci4 ,comb9$ ,gr\nd ,mold & ,lead+ ,frame = ,inv]t & ,side ,wall ,masonry #fg #dj4 ,lead+ ,frame = ,con/ruct+ ,side ,wall ,masonry #fh #da4 ,plank ,c5t] = ,con/ruct+ ! ,ro( ,ar* #fi #db4 ,truss$ ,c5t] = ,con/ruct+ ! ,ro( ,ar* #gj #dc & #dd4 ,a ,typical ,=m ( ,timb] ,l9+ = ,tunnels #gc #de4 ,diagram ,%[+ ,=ms adopt$ = ,side-,wall ,f\ndations #gf #df & #dg4 ,transv]se ,sections ( ,tunnels ,%[+ ,me?ods = ,increas+ ! ,?ickness ( ! ,l9+ at ,diff]5t ,po9ts #gi #dh4 ,refuge ,ni*e 9 ,/4 ,go?>d ,tunnel #ha #di4 ,ea/ ,portal ( ,hoosac ,tunnel #hb #ej1 #ea & #eb4 ,arrangem5t ( ,drill ,holes 9 ! ,head+ ( ,tur*9o ,tunnel #ia #ec & #ed4 ,arrangem5t ( ,drill ,holes 9 ! ,head+ ( ! ,=t ,george ,tunnel #ia #ee4 ,diagram ,%[+ ,sequ5ce ( ,excavations 9 ,drift ,me?od ( ,tunnel+ ,rock #ajb #ef4 ,sket*es ,%[+ ,sequ5ce ( ,"w 9 ,excavat+ & ,l9+ ! ,simplon ,tunnel #aaa #eg4 ,g5]al ,details ( ! ,br&t ,rot>y ,drills ,employ$ at ! ,simplon ,tunnel #aab #eh4 ,sequ5ce ( ,excavation 9 ! ,murray ,hill ,tunnel #abd #ei4 ,travel+ ,plat=m = ! ,excavation ( ! ,upp] ,side ( ! ,murray ,hill ,tunnel #abe #fj4 ,timb]+ ,us$ 9 ! ,murray ,hill ,tunnel #abf #fa4 ,diagram ,%[+ ,sequ5ce ( ,excavation 9 ,head+ ,me?od ( ,tunnel+ ,rock #acb #fb4 ,me?od ( ,/rutt+ ,ro(1 ,/4 ,go?>d ,tunnel #ace #fc4 ,sket* ,%[+ ,arrangem5t ( ,tracks1 ,/4 ,go?>d ,tunnel #ace #fd4 ,arrangem5t ( ,drill ,holes 9 ! ,=t ,george ,tunnel #acg #fe4 ,longitud9al ,section ( ! ,head+ & ,b5* ,excavation at ! ,=t ,george ,tunnel #acg #ff4 ,diagram ,%[+ ! ,arrangem5t ( ,drill ,holes 9 ! ,head+ & ,b5* ( ! ,gallits9 ,tunnel #adj #fg4 ,diagram ,%[+ ,modification ( ! ,head+ & ,b5* ,me?od #adj #fh & #fh;,a4 ,diagrams ,%[+ ,sequ5ce ( ,excavation 9 ! ,belgian ,me?od #ade #fi4 ,sket* ,%[+ ,radial ,ro( ,/rutt+1 ,belgian ,me?od #adg #gj4 ,sket* ,%[+ ,ro( ,ar* ,c5t]1 ,belgian ,me?od #adg #ga4 ,sket* ,%[+ ,me?od ( ,und]p9n+ ,ro( ,ar* ) ! ,side ,wall ,masonry #adi #gb4 ,longitud9al ,section ,%[+ ,con/ruction by ! ,belgian ,me?od #adi #gc4 ,diagram ,%[+ ,sequ5ce ( ,excavation 9 ,modifi$ ,belgian ,me?od #aeb #gd4 ,sket* ,%[+ ,failure ( ,ro( ,ar* by ,op5+ at ,cr[n #aec #ge4 ,sket* ,%[+ ,me?ods ( ,repair+ ,ro( ,ar* ,failures #aed #gf4 ,diagrams ,%[+ ,sequ5ce ( ,excavation 9 ,g]man ,me?od ( ,tunnel+ #aee #gg4 ,diagram ,%[+ ,sequ5ce ( ,excavation 9 ,wat] ,be>+ ,mat]ial1 ,g]man ,me?od #aef #gh4 ,sket* ,%[+ ,"w ( ,excavat+ & ,timb]+ ,drifts & ,head+s #aeg #gi4 ,sket* ,%[+ ,me?od ( ,ro( ,/rutt+ #aeg #hj4 ,sket* ,%[+ ,ro( ,ar* ,c5t]s & ,ar* ,con/ruction #aeh #ha4 ,sket* ,%[+ ,me?od ( ,excavat+ & ,/rutt+ ,baltimore ,belt ,l9e ,tunnel #afb #hb4 ,ro( ,ar* ,con/ruction ) ,timb] ,c5t]s1 ,baltimore ,belt ,l9e ,tunnel #afc #hc4 ,ro( ,ar* ,con/ruction ) ,iron ,c5t]s1 ,baltimore ,belt ,l9e ,tunnel #afd #hd4 ,diagram ,%[+ ,sequ5ce ( ,excavation 9 ,engli% ,me?od ( ,tunnel+ #afg #he4 ,sket*es ,%[+ ,con/ruction ( ,/rutt+1 ,engli% ,me?od #afh #hf & #hg4 ,sket*es ( ,typical ,timb] ,ro(-,ar* ,c5t]s1 ,engli% ,me?od #afi #hh4 ,sequ5ce ( ,excavation 9 ! ,am]ican ,me?od #agb #hi4 ,/rutt+ ! ,head+ 9 ! ,am]ican ,me?od #agb #ij4 ,tempor>y ,timb]+ ( ! ,ro( 9 ! ,am]ican ,me?od #agc #ia4 ,%[+ ,cr[n ,b>s ,support$ by ,segm5tal ,ar*es #agc #ib4 ,transv]sal & ,longitud9al ,section ( a ,tunnel ,excavat$ & ,/rutt$ ,accord+ to ! ,am]ican ,me?od #agd #ic & #id4 ,diagrams ,%[+ ,sequ5ce ( ,excavation 9 ,au/rian ,me?od ( ,tunnel+ #agg #ie1 #if & #ig4 ,sket*es ,%[+ ,con/ruction ( ,/rutt+1 ,au/rian ,me?od #agh #ih4 ,sket* ,%[+ ,mann] ( ,con/ruct+ ! ,l9+ ,masonry1 ,au/rian ,me?od #agi #ii4 ,diagram ,%[+ ,sequ5ce ( ,excavation 9 ,italian ,me?od ( ,tunnel+ #ahc #ajj4 ,sket* ,%[+ ,/rutt+ = ,l[] ,"p ( ,section #ahc #aja & #aja;,a4 ,sket*es ,%[+ ,con/ruction ( ,c5t]s1 ,italian ,me?od #ahd #ajb4 ,sket* ,%[+ ,inv]t & ,f\ndation ,masonry1 ,italian ,me?od4 #ahe #ajc4 ,sket* ,%[+ ,longitud9al ,section ( a ,tunnel "u ,con/ruction1 ,italian ,me?od #ahf #ajd4 ,sket* ,%[+ ,sequ5ce ( ,excavation1 ,/azza ,tunnel #ahf #aje4 ,sket* ,%[+ ,me?od ( ,/rutt+ ,fir/ ,drift1 ,/azza ,tunnel #ahg #ajf & #ajg4 ,sket*es ,%[+ ,tempor>y ,/rutt+ ,ar* ,con/ruction1 ,/azza ,tunnel #ahg #ajh4 ,sket* ,%[+ ,prelim9>y ,dra9age ,gall]ies1 ,quicks& ,me?od #aij #aji4 ,sket* ,%[+ ,con/ruction ( ,ro( ,/rutt+1 ,quicks& ,me?od #aij #aaj4 ,sket* ,%[+ ,con/ruction ( ,masonry ,l9+1 ,quicks& ,me?od #aia #aaa4 ,sket* ,%[+ ,pilot ,me?od ( ,tunnel+ #aic #aab4 ,diagram ,%[+ ,sequ5ce ( ,con/ruction 9 ,op5-,cut ,tunnels #aig #aac4 ,sket* ,%[+ ,me?od ( ,timb]+ ,op5-,cut ,tunnels1 ,d\ble ,p>allel ,tr5* ,me?od #aih #aad4 ,side-,wall ,f\ndation ,con/ruction ,op5-,cut ,tunnels #aih #aae4 ,wide-,ar* ,section1 ,bo/on ,subway #bjd #aaf4 ,d\ble-,b>rel ,section1 ,bo/on ,subway #bje #aag4 ,f\r-,track ,rectangul> ,section1 ,bo/on ,subway #bjf #aah4 ,section ,%[+ ,slice ,me?od ( ,con/ruction1 ,bo/on ,subway #bjf #aai4 ,d\ble-,track ,section1 ,new ,york ,rapid ,transit ,railway #bab #abj4 ,p>k ,av5ue ,deep ,tunnel ,con/ruction1 ,new ,york ,rapid ,transit ,railway #bad #aba4 ,h>lem ,riv] ,tunnel1 ,new ,york ,rapid ,transit ,railway #bae #abb4 ,sket* ,%[+ ,und]gr\nd ,/ream1 ,milwaukee ,wat]-,works ,tunnel #bbi #abc4 ,sket* ,%[+ ,me?ods ( ,l9+1 ,milwaukee ,wat]-,works ,tunnel #bcb #abd4 ,longitud9al ,section ( ,brunel's ,%ield1 ,fir/ ,?ames ,tunnel #bda #abe4 ,fir/ ,%ield ,inv5t$ by ,b>l[ #bdb #abf4 ,second ,%ield ,inv5t$ by ,b>l[ #bdc #abg4 ,%ield ,sugge/$ by ,grea!ad = ! ,propos$ ,nor? & ,s\? ,woolwi* ,subway #bde #abh4 ,bea*'s ,%ield ,us$ on ,broadway ,pneumatic ,railway ,tunnel #bde #abi4 ,%ield = ,city & ,s\? ,london ,railway #bdf #acj4 ,%ield = ,/4 ,clair ,riv] ,tunnel #bdg #aca4 ,%ield = ,blackwall ,tunnel #bdh #acb4 ,elliptical ,%ield = ,cli*y ,sew] ,tunnel1 ,p>is #bdi #acc4 ,semi-,elliptical ,%ield = ,cli*y ,sew] ,tunnel #bej #acd4 ,ro( ,%ield = ,bo/on ,subway #bea #ace4 ,transv]sal & ,longitud9al ,section ( ,prel9i's ,%ield #beb #acf4 ,elevation & ,section ( ,hydraulic ,jack1 ,ea/ ,riv] ,gas ,tunnel #bfj #acg4 ,ca/-,iron ,l9+1 ,/4 ,clair ,riv] ,tunnel #bfb #ach4 ,g5]al ,elevations & ,sections ( ,%ields #bgj #aci4 ,plan & ,elevation ( ,fir/ ,bulkhead ,wall 9 ,s\? ,tube1 ,manhattan #bgc #adj4 ,typical ,cross-,sections ( ,"o ,tube ( ,p5nsylvania ,railroad ,tunnel "u ! ,hudson ,riv] #bgh #ada4 ,sections ( ,c(f]dam1 ,van ,bur5 ,/4 ,tunnel1 ,*icago #bhc #adb4 ,%[+ ,work+ ,plat=ms & ,piles ,sunk 9 ,dr$g$ ,*annel #bhf #adc4 ,%[+ ,%eet+-,piles = ! ,sides ( ! ,caisson & ,truss$ ,beam = ! ,ro( #bhg #add4 ,%[+ ! ,caisson ) ! ,work+-,*amb] #bhg #ade4 ,%[+ ! ,tunnel ,con/ruct$ )9 ! ,caisson #bhi #adf4 ,%[+ ,sides ( ! ,caisson & ,supports = ! ,ro( #bij #adg4 ,%[+ ! ,ro( ( ! ,caisson ,=m$ by ! ,upp] ,half ( ! ,tunnel #bia #adh4 ,%[+ ! ,tunnel ,complet$ by ,build+ ! ,l[] ,half )9 ! ,caisson #bib #adi4 ,transv]sal ,section ( ! ,caissons = ! ,tunnel "u ! ,se9e ,riv] #bid #aej4 ,%[+ ! ,jo9+ ( ! ,caissons at ! ,pont ,mirabeau ,tunnel "u ! ,se9e ,riv] #bie #aea4 ,cross-,sections & ,plans ( ! ,detroit ,riv] ,tunnel #bih #aeb4 ,tunnel+ ?r\gh ,cav$ ,mat]ial by ,head+ #cjf #aec4 ,tunnel+ ?r\gh ,cav$ ,mat]ial by ,drifts #cjg #aed & #aee4 ,fill+ 9 ,ro( ,cavity ,=m$ by ,fall+ ,mat]ial #cjg #aef4 ,timb]+ to ,prev5t ,l&slides at ,portal #cjh #aeg4 ,%ort5+ ,tunnel ,cru%$ by ,l&slide at ,portal #cjh #aeh4 ,ext5d+ ,tunnel ?r\gh ,l&slide at ,portal #cji #aei & #afj4 ,rel9+ ,timb]-,l9$ ,tunnel #caf #afa4 ,rel9+ ,timb]-,l9$ ,tunnel1 ,great ,nor!rn ,ry #cag #afb4 ,rel9+ ,timb]-,l9$ ,tunnel1 ,great ,nor!rn ,ry #cah #afc4 ,rel9+ ,timb]-,l9$ ,tunnel1 ,great ,nor!rn ,ry #cai #afd4 ,con/ruction ( ,c5t]+ ,mullan ,tunnel #cbj #afe4 ,c5t]+ ,mullan ,tunnel #cba #aff4 ,rel9+ ,timb]-,l9$ ,tunnel1 ,norfolk ,we/]n ,ry #cbb #afg4 ,rel9+ ,timb]-,l9$ ,tunnel1 ,norfolk ,we/]n ,ry #cbc ,,introduction ,,! ,,hi/orical ,,developm5t ,,( ,,tunnel ,,build+4 ,a tunnel1 def9$ z an eng9e]+ /ructure1 is an artificial gall]y1 passage1 or roadway b5ea? ! gr\nd1 "u ! b$ ( a /ream1 or ?r\gh a hill or m\nta94 ,! art ( tunnel+ has be5 kn[n to man s9ce v anci5t times4 ,a ,!ban k+ on asc5d+ ! ?rone began at once to drive ! long1 n>r[ passage or tunnel lead+ to ! inn] *amb] or sepul*] ( ! rock-cut tomb :i* 0 to =m 8 f9al re/+-place4 ,"s ( ^! rock-cut gall]ies ( ! anci5t ,egyptian k+s 7 ov] #gej ft4 long4 ,simil> rock-cut tunnel+ "w 0 p]=m$ by ! ,nubians & ,indians 9 build+ _! temples1 by ! ,aztecs 9 ,am]ica1 & 9 fact by mo/ ( ! anci5t civiliz$ peoples4 ,! fir/ built-up tunnels ( :i* !re are any exi/+ records 7 ^? con/ruct$ by ! ,assyrians4 ,! vault$ dra9 or passage "u ! s\!a/ palace ( ,nimrud1 built by ,%almanes] ,,ii4 7#hfj-hbd ,b4,c471 is 9 all ess5tials a true s(t-gr\nd tunnel1 ) a masonry l9+4 ,a mu* bett] example1 h[ev]1 is ! tunnel "u ! ,euphrates ,riv]1 :i* may q accurately be claim$ z ! fir/ subm>9e tunnel ( :i* !re exi/s any record4 ,x 01 h[ev]1 built "u ! dry b$ ( ! riv]1 ! wat]s ( :i* 7 tempor>ily div]t$1 & !n turn$ back into _! normal *annel aft] ! tunnel "w 0 complet$1 ?us mak+ x a true subm>9e tunnel only :5 f9i%$4 ,! ,euphrates ,riv] tunnel 0 built ?r\gh s(t gr\nd1 & 0 l9$ ) brick masonry1 hav+ int]ior dim5sions ( #ab ft4 9 wid? & #ae ft4 9 height4 ,only h& labor 0 employ$ by ^! anci5t peoples 9 _! tunnel "w4 ,9 s(t gr\nd ! tools us$ 7 ! pick & %ovels1 or scoops4 ,= rock "w !y possess$ a great] range ( appliances4 ,rese>* has %[n t among ! ,egyptians1 by :om ! art ( qu>ry+ 0 highly develop$1 use 0 made ( tube drills & saws provid$ ) cutt+ edges ( corundum or o!r h>d1 gritty mat]ial4 ,! usual tools = rock "w 71 h[ev]1 ! hamm]1 ! *isel1 & w$ges2 & ! excell5ce & magnitude ( ! works accompli%$ by ^! limit$ appliances atte/ ! unlimit$ "t & labor :i* mu/ h be5 available = _! accompli%m5t4 ,! ,romans %\ld d\btless rank z ! greate/ tunnel build]s ( antiquity1 9 ! numb]1 magnitude1 & useful "* ( _! works1 & 9 ! improvem5ts :i* !y devis$ 9 ! me?ods ( tunnel build+4 ,!y introduc$ fire z an ag5t = ha/5+ ! break+ d[n ( ! rock1 & also develop$ ! famili> pr9ciple ( prosecut+ ! "w at sev]al po9ts at once by means ( %afts4 ,9 _! use ( fire ! ,romans simply took practical advantage ( ! famili> fact t :5 a heat$ rock is sudd5ly cool$ x cracks & breaks s t its excavation becomes comp>atively easy4 ,_! me?od ( op]ation 0 simply to build l>ge fires 9 front ( ! rock to be brok5 d[n1 & :5 x _h rea*$ a high temp]ature to cool x sudd5ly by ?r[+ wat] ^u ! hot surface4 ,! ,romans 7 also aw>e t v9eg> affect$ calc>e\s rock1 & 9 excavat+ tunnels ?r\gh ?is mat]ial x 0 a common practice ) !m to sub/itute v9eg> = wat] z ! cool+ ag5t1 & ?us to attack ! rock bo? *emically & me*anically4 ,x is h>dly necess>y to say t ?is me?od ( excavation 0 v sev]e on ! workm5 because ( ! heat & f\l gases g5]at$4 ,?is 01 h[ev]1 a matt] ( small conc]n to ! build]s1 s9ce ! "w 0 usually p]=m$ by slaves & prison]s ( w>1 :o p]i%$ by ?\s&s4 ,to be s5t5c$ to labor on ,roman tunnel works 0 ?us "o ( ! sev]e/ p5alties to :i* a slave or prison] c\ld be condemn$4 ,!y 7 places ( suff]+ & dea? z are to-day ! ,spani% m]cury m9es4 ,besides _! use ( fire z an excavat+ ag5t1 ! ,romans possess$ a v p]fect k ( ! use ( v]tical %afts 9 ord] to prosecute ! excavation at sev]al diff]5t po9ts simultane\sly4 ,pl9y is au?ority#a = ! /atem5t t 9 ! excavation ( ! tunnel = ! dra9age ( ,lake ,fuc9o =ty %afts & a numb] ( incl9$ gall]ies 7 sunk along its l5g? ( #c miles1 "s ( ! %afts be+ #djj ft4 9 dep?4 ,! spoil 0 hoi/$ out ( ^! %afts 9 copp] pails ( ab\t t5 gallons' capacity by w9dlasses4 #a 8,tunnel+10 ,encly4 ,brit41 #ahhi1 vol4 xxiii41 p4 #fbc4 ,! ,roman tunnels 7 design$ = public utility4 ,among ^? :i* are mo/ notable 9 ?is respect1 z well z = be+ f9e examples ( tunnel "w1 may be m5tion$ ! num]\s conduits driv5 ?r\gh ! calc>e\s rock betwe5 ,subiaco & ,tivoli to c>ry to ,rome ! pure wat] f ! m\nta9s above ,subiaco4 ,?is "w 0 done "u ! ,consul ,m>cius4 ,! longe/ ( ! ,roman tunnels is ! "o built to dra9 ,lake ,fuc9o1 z m5tion$ above4 ,?is tunnel 0 design$ to h a section ( #f ft4 #aj ft42 b its actual dim5sions are n uni=m4 ,x 0 driv5 ?r\gh calc>e\s rock1 & x is /at$ t #cj1jjj m5 7 employ$ = elev5 ye>s 9 its con/ruction4 ,! tunnels :i* h be5 m5tion$1 be+ design$ = conduits1 7 ( small section2 b ! ,romans also built tunnels ( l>g] sections at num]\s po9ts along _! magnific5t roads4 ,"o ( ! mo/ notable ( ^! is t :i* gives ! road betwe5 ,naples & ,pozzuoli passage ?r\gh ! ,posilipo hills4 ,x is excavat$ ?r\gh volcanic tufa1 & is ab\t #cjjj ft4 long & #be ft4 wide1 ) a section ( ! =m ( a po9t$ ar*4 ,9 ord] to facilitate ! illum9ation ( ?is tunnel1 its floor & ro( 7 made gradually conv]g+ f ! ends t[>d ! middle2 at ! entrances ! section 0 #ge ft4 high1 :ile at ! c5t] x 0 only #bb ft4 high4 ,?is d\ble funnel-l con/ruction caus$ ! rays ( light ent]+ ! tunnel to conc5trate z !y approa*$ ! c5t]1 & ?us to improve ! natural illum9ation4 ,! tunnel is on a grade4 ,x 0 probably excavat$ dur+ ! "t ( ,augu/us1 al?\gh "s au?orities place its con/ruction at an e>li] date4 ,dur+ ! ,middle ,ages ! art ( tunnel build+ 0 practic$ = milit>y purposes1 b seldom = ! public ne$ & com=t4 ,m5tion is made ( ! fact t 9 #adej ,anne ( ,lusignan comm5c$ ! con/ruction ( a road tunnel "u ! ,col di ,t5da 9 ! ,pi$montese ,alps to af=d bett] communication betwe5 ,nice & ,g5oa2 b on acc\nt ( its _m difficulties ! "w 0 nev] complet$1 al?\gh x 0 sev]al times ab&on$ & resum$4 ,= ! mo/ "p1 !re=e1 ! tunnel "w ( ! ,middle ,ages 0 int5d$ = ! purposes & necessities ( w>4 ,e ca/le _h its private und]gr\nd passage f ! c5tral t[] or keep to "s di/ant conceal$ place to p]mit ! escape ( ! family & its reta9]s 9 case ( ! victory ( ! enemy1 &1 dur+ ! def5se1 to all[ ( sorties & ! entrance ( supplies4 ,! tunnel build]s ( ! ,middle ,ages add$ little to ! k ( _! art4 ,inde$1 until ! #ag? c5tury & ! inv5tion ( gunp[d] no practical improvem5t 0 made 9 ! tunnel+ me?ods ( ! ,romans4 ,engrav+s ( m9+ op]ations 9 t c5tury %[ t und]gr\nd excavation 0 accompli%$ by ! pick or ! hamm] & *isel1 & t wood fires 7 light$ at ! ends ( ! head+s to split & s(t5 ! rocks 9 advance4 ,al?\gh gunp[d] _h be5 previ\sly employ$ 9 m9+1 ! fir/ important use ( x 9 tunnel "w 0 at ,malpas1 ,france1 9 #afgi-ha1 9 ! tunnel = ! ,langu$oc ,canal4 ,?is tunnel 0 #eaj ft4 long1 #bb ft4 wide1 & #bi ft4 high1 & 0 excavat$ ?r\gh tufa4 ,x 0 left unl9$ = sev5 ye>s1 & !n 0 l9$ ) masonry4 ,) ! adv5t ( gunp[d] & canal build+ ! fir/ /rong impetus 0 giv5 to tunnel build+1 9 its mod]n s5se1 z a comm]cial & public utilit>ian con/ruction1 s9ce ! days ( ! ,roman ,empire4 ,canal tunnels ( notable size 7 excavat$ 9 ,france & ,engl& dur+ ! la/ half ( ! #ag? c5tury4 ,^! 7 all rock or h>d-gr\nd tunnels4 ,inde$1 previ\s to #ahjj ! s(t-gr\nd tunnel 0 beyond ! c\rage ( eng9e] except 9 sections ( su* small size t ! "w bett] des]ves to be call$ a drift or head+ ?an a tunnel4 ,9 #ahjc1 h[ev]1 a tunnel #bd ft4 wide 0 excavat$ ?r\gh s(t soil = ! ,/4 ,qu5t9 ,canal 9 ,france4 ,timb]+ or /rutt+ 0 employ$ to support ! walls & ro( ( ! excavation z fa/ z ! e>? 0 remov$1 & ! masonry l9+ 0 built closely foll[+ x4 ,f ! exp]i5ce ga9$ 9 ?is tunnel 7 develop$ ! v>i\s sy/ems ( s(t-gr\nd subt]ranean tunnel+ s9ce employ$4 ,x 0 by ! developm5t ( ! /eam railway1 h[ev]1 t ! art ( tunnel+ 0 to be br\ght into its pres5t prom95ce4 ,9 #ahbj-bf two tunnels 7 built on ! ,liv]pool ,man*e/] ,ry4 9 ,engl&4 ,?is 0 ! beg9n+ ( ! rapid developm5t :i* has made ! tunnel "o ( ! mo/ famili> ( eng9e]+ /ructures4 ,! fir/ railway tunnel 9 ! ,unit$ ,/ates 0 built on ! ,alleghany ,portage ,r4 ,r4 9 ,p5nsylvania 9 #ahca-cc2 & ! fir/ canal tunnel _h be5 complet$ ab\t #ac ye>s previ\sly 7#ahah-ba7 by ! ,s*uylkill ,navigation ,co41 ne> ,auburn1 ,pa4 ,x w\ld be int]e/+ & in/ructive 9 _m respects to foll[ ! rise & progress ( tunnel con/ruction 9 detail s9ce ! con/ruction ( ^! e>li] examples1 b all t may be said "h is t x 0 id5tical ) t ( ! railway4 ,! art ( tunnel+ ent]$ its la/ & greate/ phase ) ! con/ruction ( ! ,mont ,c5is tunnel 9 ,europe & ! ,hoosac tunnel 9 ,am]ica1 :i* works e/abli%$ ! utility ( ma*9e rock-drills & high explosives4 ,! ,mont ,c5is tunnel 0 built to facilitate railway communication betwe5 ,italy & ,france1 or m prop]ly betwe5 ,pi$mont & ,savoy1 ! two p>ts ( ! k+dom ( ,victor ,emmanuel ,,ii41 sep>at$ by ! ,alps4 ,x is #g4f miles long1 & passes "u ! ,col di ,frjus ne> ,mont ,c5is4 ,sommeill]1 ,grattoni1 & ,gr&is 7 ! eng9e]s ( ?is great und]tak+1 :i* 0 begun 9 #aheg1 & f9i%$ 9 #ahgb4 ,x 0 f ! close /udy ( ! v>i\s difficulties1 ! great l5g? ( ! tunnel1 & ! desire ( ! eng9e]s to f9i% x quickly1 t all ! diff]5t improvem5ts 7 develop$ :i* m>k$ ?is "w z a notable /ep 9 ! advance ( ! art ( tunnel+4 ,?us ! fir/ p[]-drill ev] us$ 9 tunnel "w 0 devis$ by ,sommeill]4 ,9 addition1 compress$ air z a motive p[] = drills1 aspirators to suck ! f\l air f ! excavation1 air compressors1 turb9es1 etc41 f\nd at ,mont ,c5is _! fir/ application to tunnel con/ruction4 ,?is important rle play$ by ! ,mont ,c5is tunnel 9 ,europe 9 introduc+ mod]n me?ods _h its c\nt]p>t 9 ,am]ica 9 ! ,hoosac tunnel complet$ 9 #ahge4 ,9 ?is "w !re 7 us$ = ! fir/ "t 9 ,am]ica p[] rock-drills1 air compressors1 nitro-glyc]9e1 electricity = fir+ bla/s1 etc4 ,!re rema9s n[ to be not$ only ! f9al developm5t 9 ! art ( s(t-gr\nd subm>9e tunnel+1 namely1 ! use ( ! %ield & metal l9+4 ,! %ield 0 inv5t$ & fir/ us$ by ,sir ,isamb>d ,brunel 9 excavat+ ! tunnel "u ! ,riv] ,?ames at ,london1 :i* 0 begun 9 #ahbe1 & f9i%$ 9 #ahda4 ,9 #ahfi ,pet] ,william ,b>l[ us$ an iron l9+ 9 connection ) a %ield 9 driv+ ! second tunnel "u ! ,?ames at ,london4 ,f ^! inv5tions has gr[n up "o ( ! mo/ notable sy/ems ( tunnel+ n[ practic$1 :i* is commonly kn[n z ! %ield sy/em4 ,9 clos+ ?is brief review ( ! developm5t ( mod]n me?ods ( tunnel+1 to ! pres5tation ( :i* ! rema9d] ( ?is book is devot$1 m5tion %\ld be made ( a =m ( motive p[] :i* promises _m opportunities = developm5t 9 tunnel con/ruction4 ,electricity has long be5 employ$ = bla/+ & illum9at+ purposes 9 tunnel "w4 ,x rema9s to be ext5d$ to o!r uses4 ,= haul+ & = op]at+ c]ta9 classes ( hoi/+ & excavat+ ma*9]y x is "o ( ! mo/ conv5i5t =ms ( p[] available to ! eng9e]4 ,its successful application to rock-drills is ano!r promis+ field4 ,= op]at+ v5tilat+ fans x promises unusual usefulness4 ,,tunnel+ ,,*apt] ,i4 ,,prelim9>y ,,consid]ations4 ,,*oice ,,betwe5 ,a ,,tunnel ,,& ,,op5 ,,cut4 ,,geological ,,surveys4 ,,*oice ,,betwe5 ,a ,,tunnel ,,& ,,an ,,op5 ,,cut4 ,:5 a railway l9e is to be c>ri$ across a range ( m\nta9s or hills1 ! fir/ "q :i* arises is :e!r x is bett] to con/ruct a tunnel or to make su* a dt\r z w enable ! ob/ruction to be pass$ ) ord9>y surface con/ruction4 ,! answ] to ?is "q dep5ds ^u ! comp>ative co/ ( con/ruction & ma9t5ance1 & ^u ! relative comm]cial & /ructural advantages & disadvantages ( ! two me?ods4 ,9 favor ( ! op5 road !re are its small] co/ & ! decreas$ "t requir$ 9 its con/ruction4 ,^! mean t less capital w be requir$1 & t ! road w soon] be able to e>n some?+ = its build]s4 ,aga9/ ! op5 road !re are3 its great] l5g? & consequ5tly its heavi] runn+ exp5ses2 ! great] am\nt ( roll+-/ock requir$ to op]ate x2 ! heavy exp5se ( ma9ta9+ a m\nta9 road2 & ! necessity ( employ+ l>g] locomotives1 ) ! increas$ exp5ses :i* !y entail4 ,9 favor ( ! tunnel !re are3 ! %ort5+ ( ! road1 ) ! consequ5t decrease 9 ! op]at+ exp5ses & am\nt ( roll+-/ock requir$2 ! small] co/ ( ma9t5ance1 ow+ to ! protection ( ! track f sn[ & ra9 & o!r natural influ5ces caus+ det]ioration2 & ! decreas$ co/ ( haul+ due to ! light] grades4 ,aga9/ ! tunnel1 !re are its enorm\s co/ z comp>$ ) an op5 road & ! great l5g? ( "t requir$ to con/ruct x4 ,to det]m9e 9 any p>ticul> case :e!r a tunnel or an op5 road is be/1 requires a c>eful integration ( all ! factors m5tion$4 ,x may be ass]t$ 9 a g5]al way1 h[ev]1 t ! enorm\s advance made 9 ! art ( tunnel build+ has done mu* to less5 ! /r5g? ( ! pr9cipal objections to tunnels1 namely1 _! great co/ & ! l5g? ( "t requir$ = _! con/ruction4 ,:]e ! *oice lies betwe5 a tunnel or a long dt\r ) heavy grades x is soon] or lat] almo/ always decid$ 9 favor ( a tunnel4 ,:51 h[ev]1 ! conditions are su* t ! *oice lies betwe5 a tunnel or a heavy op5 cut ) ! same grades ! problem ( decid+ betwe5 ! two solutions is a m difficult "o4 ,x is g5]ally assum$ t :5 ! cut requir$ w h a v]tical dep? exce$+ #fj ft4 x is less exp5sive to build a tunnel unless ! excavat$ mat]ial is ne$$ = a ne>by embankm5t or fill4 ,?is rule is n absolute1 b v>ies accord+ to local conditions4 ,= in/ance1 9 mat]ials ( rigid & unyield+ "*1 su* z rock1 ! practical limit to ! dep? ( a cut goes f> beyond t po9t at :i* a tunnel w\ld be m economical accord+ to ! above rule4 ,9 soils ( a yield+ "*1 on ! o!r h&1 ! v flat slope requir$ = /ability adds greatly to ! co/ ( mak+ a cut4 ,x may be not$ 9 clos+ t ! same rule may be employ$ 9 det]m9+ ! location ( ! ends ( ! tunnel1 = assum+ t x is m conv5i5t to excavate a tunnel ?an an op5 cut :5 ! dep? exce$s #fj ft41 !n ! op5 cut approa*es %\ld ext5d into ! m\nta9- or hill-sides only to ! po9ts :]e ! surface is #fj ft4 above grade1 & !re ! tunnel %\ld beg94 ,if1 !re=e1 we draw on ! longitud9al pr(ile ( ! tunnel a l9e p>allel to ! plane ( ! tracks1 & #fj ft4 above x1 ?is l9e w cut ! surface at ! po9ts :]e ! op5-cut approa*es %\ld cease & ! tunnel beg94 ,?is is a rule-(-?umb det]m9ation at ! be/1 & requires judgm5t 9 its use4 ,%\ld ! gr\nd surface1 = example1 rise only a few feet above ! #fj ft4 l9e = any di/ance1 x is obvi\sly bett] to cont9ue ! op5 cut ?an to tunnel4 ,,! ,,me?od ,,& ,,purpose ,,( ,,geological ,,surveys4 ,:5 x has be5 decid$ to build a tunnel1 ! fir/ duty ( ! eng9e] is to make an accurate geological survey ( ! locality4 ,f ?is survey ! mat]ial p5etrat$1 ! =m ( section & k9d ( /rutt+ to be us$1 ! be/ =m ( l9+ to be adopt$1 ! co/ ( excavation1 & v>i\s o!r facts1 are to be d$uc$4 ,9 small tunnels ! geological k ( ! eng9e] %\ld enable him to con/ruct a geological map ( ! locality1 or ?is k may be _h 9 _m cases by consult+ ! geological maps issu$ by ! ,/ate or g5]al gov]nm5t surveys4 ,:51 h[ev]1 ! tunnel is to be ( great l5g?1 x may be necess>y to call 9 ! assi/ance ( a pr(essional geologi/ 9 ord] to recon/ruct accurately ! int]ior ( ! m\nta9 & !reby to asc]ta9 be=eh& ! diff]5t /rata & mat]ials to be excavat$1 ?us obta9+ ! data = calculat+ bo? ! "t & co/ ( excavat+ ! tunnel4 ,! geological survey %\ld enable ! eng9e] to det]m9e1 7#a7 ! "* ( ! mat]ial & its =ce ( cohesion1 7#b7 ! incl9ation ( ! diff]5t /rata1 & 7#c7 ! pres5ce ( wat]4 ,"* ( ,mat]ial4--,! "* ( ! mat]ial ?r\gh :i* ! propos$ tunnel w p5etrate is be/ asc]ta9$ by means ( diamond rock-drills4 ,^! ma*9es bore an annul> hole1 & take away a core = ! :ole dep? ( ! bor+1 ?us giv+ a p]fect geological section %[+ ! "*1 succession1 & exact ?ickness ( ! /rata4 ,by mak+ su* bor+s at diff]5t po9ts along ! c5t] l9e ( ! project$ tunnel1 & comp>+ ! relative sequ5ce & ?ickness ( ! diff]5t /rata %[n by ! cores1 ! geological =mation ( ! m\nta9 may be det]m9$ q exactly4 ,:]e x is difficult or impracticable to make diamond drill bor+s on acc\nt ( ! dep? ( ! m\nta9 above ! tunnel1 or because ( its inaccessibility1 ! eng9e] mu/ resort to o!r me?ods ( obs]vation4 ,! pres5t =ms ( m\nta9s or hills are due to wea!r+1 or ! action ( ! de/ructive atmosph]ic influ5ces ^u ! orig9al mat]ial4 ,f ! mann] 9 :i* ! m\nta9 or hill has resi/$ wea!r+1 !re=e1 may be d$uc$ 9 a g5]al way bo? ! nature & consi/5cy ( ! mat]ials ( :i* x is compos$4 ,?us we %all g5]ally f9d m\nta9s or hills ( r\nd$ outl9es to consi/ ( s(t rocks or loose soils1 :ile "u v /eep & cre/$ m\nta9s h>d rock usually exi/s4 ,to ! g5]al k ( ! nature ( its int]ior ?us af=d$ by ! ext]ior =m ( ! m\nta91 ! eng9e] mu/ add su* in=mation z ! surface outcropp+s & o!r local evid5ces p]mit4 ,= ! purposes ( ! tunnel build] we may fir/ classify all mat]ials z ei!r1 7#a7 h>d rock1 7#b7 s(t rock1 or 7#c7 s(t soil4 ,h>d rocks are ^? hav+ suffici5t cohesion to /& v]tically :5 cut to any dep?4 ,_m ( ! prim>y rocks1 l granite1 gneiss1 feldsp>1 & basalt1 belong to ?is class1 b o!rs ( ! same gr\p are affect$ by ! atmosph]e1 moi/ure1 & fro/1 :i* gradually dis9tegrate !m4 ,!y are also (t5 f\nd int]sp]s$ ) pyrites1 ^: well-kn[n t5d5cy to dis9tegrate ^u exposure to air introduces ano!r de/ructive ag5cy4 ,= ^! reasons we may divide h>d rocks into two sub-classes2 viz41 h>d rocks unaffect$ by ! atmosph]e1 & ^? affect$ by x4 ,?is di/9ction is *iefly important 9 tunnel+ z det]m9+ :e!r or n a l9+ w be requir$4 ,s(t rocks1 z ! t]m implies1 are ^? 9 :i* ! =ce ( cohesion is less ?an 9 h>d rocks1 & :i* 9 consequ5ce (f] less resi/ance to attacks t5d+ to break d[n _! orig9al /ructure4 ,!y are always affect$ by ! atmosph]e4 ,s&/ones1 lam9at$ clay %ales1 mica-s*i/s1 & all s*i/ose /ones1 *alk & "s volcanic rocks1 c be classifi$ 9 ?is gr\p4 ,s(t rocks require to be support$ by timb]+ dur+ excavation1 & ne$ to be protect$ by a /rong l9+ to exclude ! air1 & to support ! v]tical pressures1 & prev5t ! fall ( fragm5ts4 ,s(t soils are compos$ ( detrital mat]ials1 hav+ s little cohesion t !y may be excavat$ )\t ! use ( explosives4 ,tunnels excavat$ ?r\gh ^! soils mu/ be /rongly timb]$ dur+ excavation to support ! v]tical pressure & prev5t cav+2 & !y also always require a /rong l9+4 ,gravel1 s&1 %ale1 clay1 quicks&1 & peat are ! s(t soils g5]ally enc\nt]$ 9 ! excavation ( tunnels4 ,gravels & dry s& are ! /ronge/ & firme/2 %ales are v firm1 b !y possess ! great defect ( be+ liable to swell 9 ! pres5ce ( wat] or m]ely by exposure to ! air1 to su* an ext5t t !y h be5 kn[n to cru% ! timb]+ built to support !m4 ,quicks& & peat are prov]bially trea*]\s mat]ials4 ,clays are sometimes firm & t5aci\s1 b :5 lam9at$ & 9 ! pres5ce ( wat] are among ! mo/ trea*]\s soils4 ,lam9at$ clays may be describ$ z ord9>y clays alt]$ by *emical & me*anical ag5cies1 & sev]al modifications ( ! same /ructure are (t5 f\nd 9 ! same locality4 ,!y are compos$ ( lam9 ( l5ticul> =m sep>at$ by smoo? surfaces & easily deta*$ f ea* o!r4 ,lam9at$ clays g5]ally h a d>k color1 r$1 o*] or gre5i% blue1 & are v (t5 f\nd alt]nat+ ) /rata ( /iatites or calc>e\s mat]ial4 ,= purposes ( con/ruction !y h be5 divid$ into ?ree v>ieties4 ,lam9at$ clays ( ! fir/ v>iety are ^? :i* alt]nate ) calc>e\s /rata & are n s greatly alt]$ z to lose _! orig9al /ratification4 ,lam9at$ clays ( ! second v>iety are ^? 9 :i* ! calc>e\s /rata are brok5 & r$uc$ to small pieces1 b 9 :i* ! =m] /ructure is n completely de/roy$2 ! clay is n r$uc$ to a humid /ate4 ,lam9at$ clays ( ! ?ird v>iety are ^? 9 :i* ! clay by ! =ce ( cont9u$ di/urbance1 & 9 ! pres5ce ( wat]1 has become pla/ic4 ,lam9at$ clays are v trea*]\s soils2 quicks& & peat may be class$1 z reg>ds _! trea*]\s nature1 among ! lam9at$ clays ( ! ?ird v>iety4 ,incl9ation ( ,/rata4--,kn[+ ! incl9ation ( ! /rata1 or ! angle :i* !y make ) ! horizon1 x is easy to det]m9e :]e !y int]sect ! v]tical plane ( ! tunnel pass+ ?r\gh ! c5t] l9e1 ?us giv+ to a c]ta9 ext5t a k ( ! diff]5t /rata :i* w be met 9 ! excavation4 ,on ! incl9ation ( ! /rata dep5d3 7#a7 ,! co/ ( ! excavation2 ! bla/+1 = in/ance1 w be m effici5t if ! rocks are attack$ p]p5dicul> to ! /ratification2 7#b7 ,! "* ( ! timb]+ or /rutt+2 ! t5d5cy ( ! rock to fall is great] if ! /rata are horizontal ?an if !y are v]tical2 7#c7 ,! "* & ?ickness ( ! l9+2 horizontal /rata are 9 ! weake/ position to resi/ ! v]tical pressure f ! load above :5 depriv$ ( ! support+ rock bel[1 :ile v]tical /rata1 :5 p5etrat$1 act z a sort ( ar* to support ! pressure ( ! load above4 ,! =ego+ rem>ks apply only to h>d or s(t rock mat]ials4 ,9 detrital =mations ! incl9ation ( ! /rata is an important consid]ation1 because ( ! unsymmetrical pressures develop$4 ,9 excavat+ a tunnel ?r\gh s(t soil ^: /rata are incl9$ at #cj to ! horizon1 = in/ance1 ! tunnel w cut ^! /rata at an angle ( #cj4 ,by ! excavation ! natural equilibrium ( ! soil is di/urb$1 & :ile ! e>? t5ds to fall & settle on bo? sides at an angle dep5d+ ^u ! friction & cohesion ( ! mat]ial1 ?is angle w be mu* great] on "o side ?an on ! o!r because ( ! incl9ation ( ! /rata2 & h5ce ! prism ( fall+ e>? on "o side is great] ?an on ! o!r1 & consequ5tly ! pressures are diff]5t1 or 9 o!r words1 !y are unsymmetrical4 ,^! unsymmetrical pressures are usually easily tak5 c>e ( z f> z ! l9+ is conc]n$1 b !y may cause s]i\s cave-ins & badly di/ort ! /rutt+4 ,cav+-9 dur+ excavation may be prev5t$ by cutt+ ! mat]ials accord+ to _! natural slope2 b ! di/ortion ( ! /rutt+ is a m s]i\s problem to h&le1 & "o :i* (t5times requires ! utmo/ vigilance & c>e to prev5t s]i\s tr\ble4 ,pres5ce ( ,wat]4--,an idea ( ! likelihood ( f9d+ wat] 9 ! tunnel may be obta9$ by /udy+ ! hydrographic bas9 ( ! locality4 ,f x ! s\rce & direction ( ! spr+s1 creeks1 rav9es1 etc41 c be trac$1 & f ! geological map x c be se5 :]e ! /rata be>+ ^! wat]s meet ! c5t] l9e4 ,n only ought ! surface wat] to be att5tively /udi$1 b und]gr\nd spr+s1 :i* are frequ5tly enc\nt]$ 9 ! excavation ( tunnels1 require c>eful att5tion4 ,bo? ! surface & und]gr\nd wat]s foll[ ! p]vi\s /rata1 & are div]t$ by imp]vi\s /rata4 ,rocks g5]ally may be class$ z imp]vi\s2 b !y conta9 crevices & faults1 :i* (t5 all[ wat] to pass ?r\gh !m2 & x is1 !re=e1 n uncommon to enc\nt] l>ge quantities ( wat] 9 excavat+ tunnels ?r\gh rock4 ,z a rule1 wat] w be f\nd "u high m\nta9s1 :i* comes f ! melt$ ice & sn[ p]colat+ ?r\gh ! rock crevices4 ,"s detrital soils1 l gravel & s&1 are p]vi\s1 & o!rs1 l clay & %ale1 are imp]vi\s4 ,detrital soils ly+ above clay are almo/ c]ta9 to c>ry wat] j above ! clay /ratum4 ,9 tunnel "w1 !re=e1 :5 ! excavation keeps well )9 ! clay /ratum1 little tr\ble is likely to be _h f wat]2 %\ld1 h[ev]1 ! excavation cut ! clay surface & ent] ! p]vi\s mat]ial above1 wat] is q c]ta9 to be enc\nt]$4 ,! quantity ( wat] enc\nt]$ 9 any case dep5ds ^u ! pres5ce ( high m\nta9s ne> by1 & ^u o!r circum/ances :i* w attract ! att5tion ( ! eng9e]4 ,a k ( ! pressure ( ! wat] is desirable4 ,?is may be obta9$ by obs]v+ closely its s\rce & ! "* ( ! /rata ?r\gh :i* x passes4 ,wat] com+ to ! excavation ?r\gh rock crevices w lose little ( its pressure by friction1 :ile t :i* has pass$ "s di/ance ?r\gh s& w h lo/ a great deal ( its pressure by friction4 ,wat] be>+ s&1 &1 9 fact1 any wat] be>+ detrital mat]ial1 has its fluidity increas$ by wat] pressure2 & :5 ?is rea*es ! po9t :]e fl[ results1 tr\ble ensues4 ,! /reams ( wat] met 9 ! con/ruction ( ! ,/4 ,go?>d tunnel _h suffici5t pressure to c>ry away timb] & mat]ials4 ,,*apt] ,,ii4 ,,me?ods ,,( ,,det]m9+ ,,! ,,c5t] ,,l9e ,,& ,,=ms ,,& ,,dim5sions ,,( ,,cross-,,section4 ,,det]m9+ ,,! ,,c5t] ,,l9e4 ,tunnels may be ei!r curvil9e> or rectil9e>1 b ! latt] =m is ! m common4 ,9 ei!r case ! fir/ task ( ! eng9e]1 aft] ! ends ( ! tunnel h be5 def9itely fix$1 is to locate ! c5t] l9e exactly4 ,?is is done on ! surface ( ! gr\nd2 & its purpose is to f9d ! exact l5g? ( ! tunnel1 & to furni% a ref]5ce l9e by :i* ! excavation is direct$4 ,rectil9e> ,tunnels4--,9 %ort tunnels ! c5t] l9e may be accurately en\gh locat$ = all practical purposes by means ( a common !odolite4 ,! "w is p]=m$ on a calm1 cle> day1 s z to h ! in/rum5t & obs]vations subject$ to z little atmosph]ic di/urbance z possible4 ,wood5 /akes are employ$ to m>k ! v>i\s locat$ po9ts ( ! c5t] l9e tempor>ily4 ,! obs]vations are usually repeat$ once at lea/ to *eck ! errors1 & ! /akes are alt]$ z ! corrections dictate2 & aft] ! l9e is f9ally decid$ to be correctly fix$1 !y are replac$ by p]man5t monum5ts ( /one accurately m>k$4 ,! me?od ( *eck+ ! obs]vations is describ$ by ,mr4 ,w4 ,d4 ,haskoll#b z foll[s3 8,let ! !odolite be c>efully set up ov] "o ( ! /akes1 ) ! nail driv5 into x1 select+ "o t w comm& ! be/ position s z to range backw>ds & =w>ds ov] ! :ole l5g? ( l9e1 & also obta9 a view ( ! two di/ant po9ts t range ) ! c5t] l9e2 ?is be+ done1 let ! c5t]s ( e /ake 444 be c>efully v]ifi$4 ,if ?is be c>efully done1 & ! c5t]s be f\nd correct1 & ?or\ghly 9 "o visual l9e z se5 ?r\gh ! telescope1 !re w be no fe> b t a p]fectly /raight l9e has be5 obta9$40 #b 8,practical ,tunnel+10 by ,f4 ,w4 ,simms4 ,illu/ration3 ,,fig4 #a4--;,diagram ,%[+ ,mann] ( ,l9+ 9 ,rectil9e> ,tunnels4 ,! c5t] l9e :i* has ?us be5 locat$ on ! gr\nd surface has to be transpos$ to ! inside ( ! tunnel to direct ! excavation4 ,to d ?is let ,a & ,b be ! entrances & a & b be ! two di/9ct fix$ po9ts :i* h be5 rang$ 9 ) ! c5t] l9e locat$ on ! gr\nd surface ov] ! hill ,a f ,b1 ,fig4 #a4 ,! in/rum5t is set up at ,v1 any po9t on ! l9e ,a a produc$1 & a be>+ secur$ by obs]vation on ! c5t] l9e m>k$ on ! surface4 ,?is be>+ is !n c>ri$ into ! tunnel by plung+ ! telescope1 & sett+ pegs 9 ! ro( ( ! head+4 ,lamps hung f ^! pegs furni% ! necess>y sight+ po9ts4 ,?is same op]ation is repeat$ on ! opposite side ( ! hill to direct ! excavation f t end ( ! tunnel4 ,^! op]ations s]ve to locate only ! fir/ few po9ts inside ! tunnel4 ,z ! excavation p5etrates f>!r into ! hill1 x becomes impossible to cont9ue to locate ! l9e f ! outside po9t1 & ! l9e has to be run f ! po9ts m>k$ on ! ro( ( ! head+4 ,great accuracy is requir$ 9 all ^! obs]vations1 s9ce a v small error at ! beg9n+ becomes great] & great] z ! excavation advances4 ,to facilitate ! accurate location ( po9ts on ! ro( ( ! tunnel1 a simple device 0 design$ by ,mr4 ,bev]ley ,r4 ,value1 %[n 9 ,fig4 #b4 ,two iron spikes1 ea* hav+ a small hole 9 ! flat end1 are driv5 into ! rock ab\t #i ins4 ap>t4 ,a brass b>1 #a 94 high1 94 ?ick & #aj ins4 long1 hav+ a hole ne> "o end & a #a 94 slot at ! o!r1 is screw$ tightly into ! head ( ! spikes4 ,! middle "p ( ! b> is divid$ into in*es & t5?s ( an in*4 ,a sep>ate brass hang] is fitt$ to ! b>1 hav+ a v]ni] ) its z]o at ! middle ( ! hang] & correspond+ to a plumb l9e atta*$ bel[4 ,! hang] is mov$ back & =? until x co9cides ) ! l9e ( sight ( ! transit1 & !n ! read+s ( ! v]ni] are record$4 ,any "t t ! hang] is plac$ on ! b> & ! v]ni] m>ks ! same read+1 ! plumb l9e w indicate ! c5t] l9e ( ! tunnel4 ,:51 in/ead ( "o b>1 two are ins]t$ at a di/ance ( #bj or #cj ft4 ap>t1 ! plumb l9es susp5d$ f ! hang]s w repres5t ! v]tical plane pass+ ?r\gh ! axis ( ! tunnel 9 co9cid5ce ) ! "o /ak$ out on ! surface gr\nd4 ,illu/ration3 ,,fig4 #b4--;,b4 ,r4 ,value's ,device = ,locat+ ! ,c5t] ,l9e ,inside ( a ,tunnel4 ,! location ( ! c5t] l9e ( a long tunnel1 :i* is to be excavat$ "u high m\nta9s1 is a v difficult op]ation1 & ! eng9e]s usually leave ?is "p ( ! "w to a/ronom]s1 :o fix ! /ations f :i* ! eng9e]s direct ! "w ( con/ruction4 ,! c5t] l9es ( all ! great ,alp9e tunnels 7 locat$ by a/ronom]s :o us$ in/rum5ts ( l>ge size4 ,?us1 9 rang+ ! c5t] l9e ( ! ,/4 ,go?>d tunnel1 ! !odolite us$ _h an object glass eight in*es 9 diamet]4#c ,in/ead ( ! ord9>y m\nt+ a masonry p$e/al ) a p]fectly level top is employ$ to support ! in/rum5t dur+ ! obs]vations4 ,! location is made by means ( triangulation4 ,! v>i\s op]ations mu/ be p]=m$ ) ! greate/ accuracy1 & repeat$ sev]al times 9 su* a way z to r$uce ! errors to a m9imum1 s9ce ! f9al meet+ ( ! head+s dep5ds ^u _! elim9ation4 #c ,see also ! ,simplon ,tunnel1 ,*apt] ,x4 ,illu/ration3 ,,fig4 #c4--,triangulation ,sy/em = ,e/abli%+ ! ,c5t] ,l9e ( ! ,/4 ,go?>d ,tunnel4 ,! ,/4 ,go?>d tunnel furni%es p]haps ! be/ illu/ration ( c>eful "w 9 locat+ ! c5t] l9e ( long rectil9e> tunnels ( any tunnel ev] built4 ,! l5g? ( ?is tunnel is #i4be miles1 & ! height ( ! m\nta9 above x is v great4 ,! c5t] l9e 0 locat$ by triangulation by two diff]5t a/ronom]s us+ diff]5t sets ( triangles1 & work+ at diff]5t times4 ,! set or sy/em ( triangles us$ by ,dr4 ,koppe1 "o ( ! obs]v]s1 is %[n by ,fig4 #c2 x consi/s ( v l>ge & q small triangles comb9$1 ! latt] be+ requir$ because ! entrances bo? at ,airolo & ,goes*55 7 s l[ z to p]mit only ( a %ort sight be+ tak54 ,! apices ( ! triangles 7 locat$ by means ( ! cont\r maps ( ! ,swiss ,alp9e ,club4 ,ea* angle 0 read t5 times1 ! in/rum5t 0 collimat$ f\r times = ea* read+1 & 0 aft]w>ds turn$ (f #e or #aj to avoid errors ( graduation4 ,! av]age ( ! errors 9 read+ 0 ab\t "o second ( arc4 ,! triangulation 0 comp5sat$ accord+ to ! me?od ( lea/ squ>es4 ,! probable error 9 ! fix$ direction 0 calculat$ to be #j4h ( arc at ,goes*55 & #j4g ( arc at ,airolo4 ,f ?is x 0 assum$ t ! probable deviation f ! true c5t] w\ld be ab\t two in*es at ! middle ( ! tunnel1 b :5 ! head+s f9ally met ?is deviation 0 f\nd to rea* elev5 in*es4 ,comp>atively few tunnels are driv5 by work+ f ! entrances alone1 ! excavation be+ usually prosecut$ at sev]al po9ts at once by means ( %afts4 ,9 ^! cases1 9 ord] to direct ! excavation correctly1 x is necess>y to fix ! c5t] l9e on ! bottom ( ! %aft4 ,?is is accompli%$ 9 two ways1--"o be+ employ$ :5 ! %aft is locat$ directly ov] ! c5t] l9e1 & ! o!r :5 ! %aft is locat$ to "o side ( ! c5t] l9e4 ,:5 ! %aft is locat$ on ! c5t] l9e two small pill>s are plac$ on opposite edges ( ! %aft & collimat+ ) ! c5t] l9e z %[n by ,fig4 #d4 ,on ^! two pill>s ! po9ts correspond+ to ! c5t] l9e are correctly m>k$1 & connect$ by a wire /ret*$ betwe5 !m4 ,to ?is wire two plumb bobs are fa/5$ z f> ap>t z possible4 ,^! plumb bobs m>k two po9ts on ! c5t] l9e at ! bottom ( ! %aft1 & f !m ! l9e is ext5d$ into ! head+s z ! "w advances4 ,9 ^! op]ations1 heavy plumb bobs are us$4 ,9 ! ,new ,york subway plumb bobs ( /eel1 weigh+ #be lbs4 ea*1 7 us$1 & to prev5t rotation !y 7 made ) cross-sections1 9 ! %ape ( a ,greek cross1 & 7 sunk 9 buckets fill$ ) wat]4 ,ow+ to ! diff]5ce betwe5 ! temp]ature at ! top & t at ! bottom ( ! %aft1 /rong curr5ts ( air are produc$1 :i* keep 9 con/ant oscillation ! wires to :i* ! bobs are susp5d$4 ,illu/ration3 ,,fig4 #d4--,me?od ( ,transf]r+ ! ,c5t] ,l9e d[n ,c5t] ,%afts4 ,to det]m9e ! c5t] l9e at ! bottom ( ! %aft1 ! head+s are fir/ driv5 f bo? sides ( ! %aft1 aft] :i* a transit is set up on ! same alignm5t ) ! two wires1 & ?is w indicate ! v]tical plane pass+ ?r\gh ! axis ( con/ruction4 ,two po9ts are !n fix$ on ! ro( ( ! tunnel 9 cont9uation ( ?is v]tical plane4 ,:5 ! plumb bobs are remov$ f ! %aft & two small plumb bobs are susp5d$ to ! two po9ts m5tion$1 !y w always give ! same v]tical plane pass+ ?r\gh ! axis ( con/ruction transf]r$ f ! surface4 ,because ( ! cont9u\s mov+ ( ! wires1 ! fix+ ( ! po9ts on ! ro( ( ! tunnel is v tr\blesome1 & ! op]ation %\ld be repeat$ by diff]5t m5 at diff]5t times be=e ! po9ts are p]man5tly fix$4 ,illu/ration3 ,,fig4 #e4--,me?od ( ,transf]r+ ! ,c5t] ,l9e d[n ,side ,%afts4 ,:5 ! %aft is plac$ at "o side ( ! tunnel ! pill>s or b5* m>ks are plac$ normal to ! c5t] l9e on ! edges ( ! %aft z %[n by ,fig4 #e4 ,betwe5 ! po9ts ,a & ,b a wire is /ret*$1 & f x two plumb bobs are susp5d$1 z describ$ 9 ! prec$+ case2 ^! plumb bobs e/abli% a v]tical plane normal to ! axis ( ! tunnel4 ,! excavation ( ! side tunnel is c>ri$ along ! l9e ,,bw until x int]sects ! l9e ( ! ma9 tunnel1 ^: c5t] l9e is det]m9$ by measur+ (f und]gr\nd a di/ance equal to ! di/ance ,,bo on ! surface4 ,by sett+ ! in/rum5t ov] ! und]gr\nd po9t ,o1 & turn+ (f a "r angle f ! l9e ,,bo1 ! c5t] l9e ( ! tunnel is ext5d$ into ! head+s4 ,curvil9e> ,tunnels4--,!re are v>i\s me?ods ( locat+ ! c5t] l9es ( curvil9e> tunnels1 b ! me?od ( tang5t (fsets is ! "o mo/ commonly employ$4 ,at ! beg9n+ ! excavation is conduct$ z closely z may be to ! l9e ( ! curve1 & z soon z x has progress$ f> en\gh ! tang5t ,,at1 ,fig4 #f1 is rang$ out4 ,at ,b a po9t is locat$ ov] :i* to set ! in/rum5t1 & ! di/ance ,,ab is measur$ = ! purpose ( f9d+ ! ord9ate ( ! "r angle triangle ,,oab4 ,n[ ,,oa r1 ,,ab d1 & angle ,,abo4 ,!n3 r ,tang4 ---4 d ,illu/ration3 ,,fig4 #f4--,me?od ( ,lay+ ,out ! ,c5t] ,l9e ( ,curvil9e> ,tunnels4 ,d\bl+ ! value ( & mak+ ! angle ,,abc #b 1 ! l9e ,,bc w be fix$ & ! po9t ,c locat$ by tak+ ,,ab ,,bc4 ,on ,,bc ! ord9ates are laid (f to locate ! curve4 ,prolong ,,cb s t ,,cd ,,cb4 ,!n ! portion ( ! curve ,,cf is symmetrical ) ,,ce1 & ! ord9ates us$ to locate ,,ec may be employ$ to locate ,,cf1 by lay+ !m (f 9 ! rev]se ord]4 ,9 curvil9e> tunnels sev]al cases may be consid]$4 7#a7 ,:5 ! tunnel = almo/ its entire l5g? is driv5 on a tang5t ) a curve at ea* end4 7#b7 ,:5 ! tunnel beg9s ) a curve & ends ) a /raight l9e4 7#c7 ,:5 ! :ole tunnel is 9 curve f portal to portal4 7#d7 ,! helicoidal or corkscrew tunnel4 99 99 99 99 99 7#a7 ,! axis ( e "o ( ! great ,alp9e tunnels is a /raight l9e1 ) a curve at ea* end4 ,to range out ! c5t] l9e ( "o ( ^! long tunnels f a curve1 no matt] h[ accurately laid out1 w c]ta9ly cause an error1 :i*1 magnifi$ ) ! di/ance1 may produce s]i\s results4 ,to avoid ^! inconv5i5ces1 ! det]m9ation ( ! axis ( ! tunnel %\ld be made f a /raight l9e4 ,?is means t ! tunnel is at fir/ excavat$ on a /raight l9e = its entire l5g? & aft] ! head+s driv5 f bo? portals h met1 ! two portions ( ! tunnel or curve are excavat$ & con/ruct$4 ,! portions ( ! tunnel excavat$ on /raight l9es = conv5i5ces ( con/ruction may !n be ab&on$ or us$ 9 cases ( accid5ts or repairs4 ,:5 ! axis ( a %ort tunnel has a curve at ea* end & a /raight l9e 9 ! middle1 x is driv5 directly f ! entrances2 fir/1 h[ev]1 excavat+ ! curvil9e> portions ( ! tunnel4 ,9 su* a case x w\ld be advisable to proce$ 9 ! foll[+ mann]4 ,drive ! head+s on ! curvil9e> portions ( ! tunnel1 /ak+ out ! c5t] l9e by means ( ! (fsets f ! tang5ts4 ,at ! ends ( ! curves lay out f bo? fronts ! rectil9eal portion ( ! tunnel4 ,only v n>r[ head+s %\ld be excavat$ at fir/ :ile ! :ole section c\ld be enl>g$ ne> ! entrances4 ,! excavation ( ! head+s at ! front %\ld advance v rapidly1 9 ord] t ! head+s may meet 9 ! %orte/ possible "t4 ,:5 communication is e/abli%$1 x is comp>atively easy to correct an error result+ f driv+ ! tunnel f ! curves4 7#b7 ,:5 a tunnel beg9s ) a curve & ends ) a /raight l9e1 ! "w ( excavation %\ld proce$ f bo? ends4 ,f ! /raight end ( ! tunnel only ! head+ %\ld be driv51 :ile f ! curvil9e> end ! :ole section c\ld be op5$ at once4 ,by ?is arrangem5t ! excavation progresses sl[ly f ! curvil9e> end & rapidly f ! /raight end ( ! tunnel4 ,once communication has be5 e/abli%$ & any error correct$1 ! "w ( enl>g+ ! pr(ile ( ! tunnel may be pu%$ ) ! same activity f bo? ends4 7#c7 ,:5 ! c5t] l9e ( ! entire tunnel is a curve1 !re is m probability ( slight deviations f ! true axis ( ! propos$ "w4 ,9 su* a case x w\ld be advisable to fir/ excavate a n>r[ head+ & to conc5trate all ! ef=ts 9 driv+ ! head+s z rapidly z possible 9 ord] t !y may meet 9 ! %orte/ "t4 ,! c5t] l9e ( ^! head+s is /ak$ out by ! usual me?od ( ! (fsets f ! tang5t4 ,! enl>g+ ( ! section ( ! tunnel c\ld be comm5c$ at bo? portals & be driv5 sl[ly until ! head+s h met & any errors correct$1 :5 ! "w c\ld be pu%$ ) ! greate/ activity all along ! l9e4 7#d7 ,9 corkscrew or helicoidal tunnels ! entire c5t] l9e is on a curve4 ,9 ^! tunnels1 z a rule1 !re is a great diff]5ce ( level betwe5 ! two portals1 "o be+ mu* high] ?an ! o!r1 s c>eful att5tion %\ld be paid to ! tunnel grade4 ,work+ 9 ! limit$ spaces af=d$ by n>r[ head+s x is v probable t errors may be made 9 fix+ bo? ! alignm5t & ! grade ( ! tunnel4 ,to prev5t ^! almo/ unavoidable errors1 x w\ld be well to excavate at fir/ only ! head+s1 to /ake ! c5t] l9e 9 ! ro( ( ^! head+s & !n to lay ! grade ( ! tunnel z accurately z possible4 ,! "w on ! head+s %\ld be pu%$ z rapidly z possible 9 ord] t !y may meet quickly1 s t ! c5t] l9e1 z tempor>ily laid out1 may be correct$ & p]man5tly fix$ = ! direction ( successive op]ations4 ,9 ^! tunnels ! head+s %\ld be excavat$ ne> ! c5t] ( ! tunnel cross-section s t ! sides & ro( ( ! head+ w\ld be at "s di/ance f ! sides & ro( ( ! propos$ tunnel4 ,?is arrangem5t w easily p]mit corrections to be made 9 case any slight diff]5ce f ! true l9e 0 errone\sly made dur+ ! excavation ( ! head+s4 ,,=m ,,& ,,dim5sions ,,( ,,cross-,,section4 ,9 decid+ ^u ! sectional pr(ile ( a tunnel two factors h to be tak5 into consid]ation3 7#a7 ,! =m ( section be/ suit$ to ! conditions1 & 7#b7 ! int]ior dim5sions ( ?is section4 ,=m ( ,section4--,! =m ( ! sectional pr(ile ( a tunnel %\ld be su* t ! l9+ is ( ! be/ =m to resi/ ! pressures ex]t$ by ! unsupport$ walls ( ! tunnel excavation1 & ^! v>y ) ! "* ( ! mat]ial p5etrat$4 ,^! pressures are bo? v]tical & lat]al 9 direction2 ! ro(1 depriv$ ( support by ! excavation1 t5ds to fall1 & ! opposite sides = ! same reason t5d to slide inw>d along a plane m or less incl9$1 dep5d+ ^u ! friction & cohesion ( ! mat]ial4 ,9 "s rocks ! cohesion is s great t !y w /& v]tically1 :ile x may be v small 9 loose e>? :i* slides along a plane ^: incl9ation is directly proportional to ! cohesion4 ,f ! !ory ( resi/ance ( pr(iles we "k t ! resi/ance ( a l9e to ext]ior normal =ces is directly proportional to its degree ( curvature1 & consequ5tly inv]sely proportional to ! radius ( ! curve4 ,h5ce ! sectional pr(ile ( a tunnel excavat$ ?r\gh h>d rock1 :]e !re are no lat]al pressures ow+ to ! great cohesion ( ! mat]ial1 & hav+ to resi/ only ! v]tical pressure1 %\ld be design$ to (f] ! greate/ resi/ance at its highe/ po9t1 & ! curve mu/1 !re=e1 be %>p] !re1 & may decrease t[>d ! base4 ,9 quicks&1 mud1 or o!r mat]ial practically )\t cohesion1 ! pressures w all be normal to ! l9e ( ! pr(ile1 & a circul> section is ! "o be/ suit$ to resi/ !m4 ,^! !oretical consid]ations h be5 prov$ correct by actual exp]i5ce1 & !y may be employ$ to det]m9e 9 a g5]al way ! =m ( section to be adopt$4 ,apply+ !m to v h>d rock1 !y give u a section ) an ar*$ ro( & v]tical side walls4 ,9 s(t] mat]ials !y give u an elliptical section ) its major axis v]tical1 & 9 v s(t quicks&s & mud !y give u ! circul> section4 ,^! ?ree =ms ( cross-section & _! modifications are ! ones commonly employ$ = tunnels4 ,an important exception to ?is g5]al practice1 h[ev]1 is met ) 9 "s ( ! city und]gr\nd rapid-transit railways built ( late ye>s1 :]e a rectangul> or box section is employ$4 ,^! tunnels are usually ( small dep?1 s t ! v]tical pressures are comp>atively light1 & ! b5d+ /ra9s1 :i* !y ex]t ^u ! flat ro(1 are provid$ = by employ+ /eel gird]s to =m ! ro( l9+4 ,illu/ration3 ,,fig4 #g4--;,diagram ( ,polyc5tric ,sectional ,pr(ile4 ,f :at has be5 said x w be se5 t x is impossible to e/abli% a /&>d sectional pr(ile to suit all conditions4 ,! be/ "o = ! majority ( conditions1 & ! "o mo/ commonly employ$1 is a polyc5tric figure 9 :i* ! numb] ( c5t]s & ! l5g? ( ! radii are fix$ by ! eng9e] to meet ! p>ticul> conditions :i* exi/4 ,9 a g5]al way ?is =m ( c5t] may be consid]$ z compos$ ( two p>ts symmetrical 9 respect to ! v]tical axis4 ,fig4 #g %[s su* a pr(ile1 9 :i* ,,dh is ! v]tical axis4 ,! section is unsymmetrical 9 respect to ! horizontal axis ,,ge4 ,! upp] "p =m+ ! ro( ar* is usually a semi-circle or semi-oval1 :ile ! l[] "p1 compris+ ! side walls & inv]t ( floor1 v>ies greatly 9 outl9e4 ,sometimes ! side walls are v]tical & ! inv]t is omitt$1 z %[n by ,fig4 #h2 & sometimes ! side walls are incl9$1 ) _! bottoms brac$ ap>t by ! inv]t1 z %[n by ,fig4 #i4 ,9 m trea*]\s soils ! side walls are curv$1 & are connect$ by small curv$ sections to ! inv]t1 z %[n by ,fig4 #aj4 ,9 ! la/ example ! side walls are commonly call$ skewbacks1 & ! l[] "p ( ! section is a polyc5tric figure l ! upp] "p1 b dissimil> 9 =m4 ,9 a tunnel section ^: pr(ile is compos$ entirely ( arcs ! foll[+ conditions are ess5tial3 ,! c5t]s ( ! spr+] arcs ,ga & ,ea1 ,fig4 #g1 mu/ be locat$ on ! l9e ,,ge2 ! c5t] ( ! ro( arc b,db mu/ be locat$ on ! axis ,,hd2 ! total numb] ( c5t]s mu/ be an odd numb]2 ! radii ( ! succe$+ arcs f ,g t[>d ,d & ,e t[>d ,d mu/ decrease 9 l5g?1 & f9ally ! sum ( ! angles subt5d$ by ! sev]al arcs mu/ equal #ahj4 ,illu/ration3 ,fig4 #h ,fig4 #i ,fig4 #aj ,,figs4 #h to #aj4--,typical ,sectional ,pr(iles = ,tunnel4 ,dim5sions ( ,section4--,! dim5sions to be giv5 to ! cross-section ( a tunnel dep5d ^u ! purpose = :i* x is to be us$4 ,:atev] ! purpose ( ! tunnel1 ! foll[+ ?ree po9ts h to be consid]$ 9 det]m9+ ! size ( its cross-section3 7#a7 ,! size ( cle> op5+ requir$2 7#b7 ! ?ickness ( l9+ masonry necess>y2 & 7#c7 ! decrease 9 ! cle> op5+ f ! de=mation ( ! l9+4 ,railway tunnels may be built ei!r to accommodate "o or two1 ?ree & f\r tracks4 ,9 s+le-track tunnels a cle> space ( at lea/ #b ft4 on ea* side %\ld be all[$ = betwe5 ! tunnel wall & ! side ( ! l>ge/ /&>d locomotive or c>1 & a cle> space ( at lea/ #c ft4 %\ld be all[$ = betwe5 ! ro( & ! top ( ! same locomotive or c>4 ,s9ce ! ro( ( ! tunnel is ar*-%ap$1 to secure a cle>ance ( #c ft4 at e po9t w necessitate mak+ ! cle>ance at ! c5t] great] ?an ?is am\nt4 ,9 d\ble-track tunnels ! same am\nts ( side & ro( cle>ances h to be provid$ =1 &1 9 addition1 !re has to be a cle>ance ( at lea/ #b ft4 betwe5 tra9s4 ,on ! ?ree- & f\r-track tunnels only ! wid? v>ies :ile ! height rema9s almo/ equal to ! two track4 ,ref]r+ to ,fig4 #g1 & assum+ ! l9e ,,ab to repres5t ! level ( ! tracks1 !n ! ord9>y dim5sions 9 feet requir$ = bo? s+le- & d\ble-track tunnels are z foll[s3-- ---------------------------------------- ----------------- ,,height1 ,,wid?1 ,,height1 ,,height1 ,d4 ,f4 ,g4 ,e4 ,c4 ,f4 ,c4 ,h4 ,,feet4 ,,feet4 ,,feet4 ,,feet4 ---------------------------------------- ----------------- ,s+le track#ag4f to #ahaf4e to #ahf to #g4d to ,,ab ,d\ble track#bf4f to #bhbf4f to #bhf4c to #f4i to ,,ab ---------------------------------------- ----------------- ,! dim5sions ( tunnels built = aqu$uct purposes are det]m9$ s z to h an area ( cross-section equal to ! requir$ wat]way4 ,9 ! ,croton ,aqu$uct two diff]5t types ( cross-sections 7 us$1 ! circul> "o = tunnels ?r\gh rock & ! horse%oe section = tunnels ?r\gh loose mat]ials4 ,9 ! ,catskill aqu$uct ?ree diff]5t cross-sections h be5 select$1 ! circul> "o = tunnels "u pressure & ! horse%oe = tunnels at ! hydraulic gradi5t4 ,^!1 h[ev]1 ?r\gh rock h a cross-section =m$ ( a semi-circul> ar* & v]tical side walls1 :ile ?r\gh e>? ! semi-circul> ar* is support$ by skewback walls4 ,9 tunnels built = railroad aqu$uct sew] & any o!r purpose ! ?ickness ( ! masonry l9+ to be all[$ = v>ies ) ! mat]ial p5etrat$1 z w be expla9$ 9 a succe$+ *apt] :]e ! dim5sions = v>i\s ord9>y conditions are giv5 9 tabul> =m4 ,! l9+ masonry is subject to de=mation 9 ?ree ways3 by ! s9k+ ( ! :ole masonry /ructure1 by ! squeez+ toge!r ( ! side walls by ! lat]al pressures1 & by ! settl+ ( ! ro(-ar*4 ,! :ole masonry /ructure nev] s9ks m ?an ?ree or f\r in*es1 & m]its little att5tion4 ,! movem5t ( ! side walls t[>ds ea* o!r1 :i* may am\nt to ?ree or f\r in*es = ea* wall )\t endang]+ _! /ability1 has1 h[ev]1 to be all[$ =2 & simil> all[ance mu/ be made = ! settl+ ( ! ro(-ar*1 :i* may am\nt to f n9e in*es to two feet1 :5 ! ar* is built fir/ z 9 ! ,belgian sy/em & re/s = "s "t ^u ! loose soil4 ,,*apt] ,,iii4 ,,excavat+ ,,ma*9es ,,& ,,rock ,,drills3 ,,explosives ,,& ,,bla/+4 ,e>?-,excavat+ ,ma*9es4--,comp>atively few ( ! labor-sav+ ma*9es employ$ = break+ up & remov+ loose soil 9 ord9>y surface excavation are us$ 9 tunnel excavation ?r\gh ! same mat]ial4 ,sev]al =ms ( tunnel excavat+ ma*9es h be5 tri$ at v>i\s times1 b only a few ( !m h atta9$ any measure ( success1 & ^! h seldom be5 employ$ 9 m ?an a s+le "w4 ,9 ! ,c5tral ,london und]gr\nd railway "w ?r\gh clay a cont9u\s bucket excavator 7,fig4 #aa7 0 employ$ ) consid]able sav+ 9 "t & labor ov] h& "w4 ,9 "s rec5t tunnel "w 9 ,am]ica ! contractors made q successful use ( a modifi$ =m ( /eam %ovel4 ,^! are ! mo/ rec5t attempts to use excavat+ ma*9es 9 s(t gr\nd1 & !y1 l all previ\s attempts1 mu/ be class$ z exp]im5ts r ?an z examples ( common practice4 ,! ,?omson ma*9e1#d h[ev]1 c be employ$ 9 any tunnel driv5 ?r\gh loose soil4 ,x occupies a comp>atively small space & may easily "w :5 ! timb]+ is us$ to support ! ro( ( ! tunnel4 ,/eam %ovel in/ead may give effici5t result only 9 ! case t ! :ole section ( ! tunnel is op5 at once & !re are no timb]s to prev5t ! free sw++ ( ! dipp] h&le & boom4 ,b 9 tunnels ?r\gh loose soils x is almo/ impossible to op5 ! :ole section at once )\t ! necessity ( support+ ! ro(4 ,consequ5tly ! use ( /eam %ovel 9 loose tunnels is v limit$4 ,! %ovel1 ! spade1 & ! pick1 wield$ by h&1 are ! /&>d tools n[1 z 9 ! pa/1 = excavat+ s(t-gr\nd tunnels4 #d ,! ma*9e 0 design$ by ,mr4 ,?omas ,?omson1 ,eng9e] = ,messrs4 ,walt] ,scott ,co4 ,illu/ration3 ,,fig4 #aa4--,s(t ,gr\nd ,bucket ,excavat+ ,ma*9e3 ,c5tral ,london ,und]gr\nd ,railway4 ,rock-,excavat+ ,ma*9es4--,at "o p]iod dur+ ! "w ( con/ruct+ ! ,hoosac tunnel consid]able att5tion 0 devot$ to ! developm5t ( a rock excavat+1 bor+1 or tunnel+ ma*9e4 ,?is device 0 design$ to cut a groove ar\nd ! circumf]5ce ( ! tunnel ?irte5 in*es wide & tw5ty-f\r feet 9 diamet] by means ( revolv+ cutt]s4 ,x prov$ a failure1 z did "o ( small] size1 eight feet 9 diamet]1 tri$ subsequ5tly4 ,dur+ & be=e ! ,hoosac tunnel "w a numb] ( bor+-ma*9es ( simil> "* 7 exp]im5t$ ) at ! ,mont ,c5is tunnel & else:]e 9 ,europe2 b1 l ! ,am]ican devices1 !y 7 f9ally ab&on$ z impracticable4 ,h& ,drills4--,briefly describ$1 a drill is a b> ( /eel hav+ a *isel-%ap$ end or cutt+-edge4 ,! simple/ =m ( h& drill is work$ by "o man1 :o holds ! drill 9 "o h&1 & drives x ) a hamm] wield$ by 8 o!r h&4 ,a m effici5t me?od ( h&-drill "w is1 h[ev]1 :]e "o man holds ! drill1 & ano!r sw+s ! hamm] or sl$ge4 ,ano!r =m ( h& drill1 call$ a *urn drill1 consi/s ( a long1 heavy b> ( /eel1 :i* is alt]nately rais$ & dropp$ by ! workman1 ?us cutt+ a hole by repeat$ impacts4 ,9 drill+ by h& ! workman hold+ ! drill gives x a p>tial turn on its axis at e /roke 9 ord] to prev5t w$g+ & to (f] a fre% surface to ! cutt+-edge4 ,= ! same reason ! *ips & du/ :i* accumulate 9 ! drill-hole are frequ5tly remov$4 ,! in/rum5ts us$ = ?is purpose are call$ scrap]s or dipp]s1 & are usually v simple 9 con/ruction4 ,a common =m is a /rong wire hav+ its end b5t at "r angles1 & flatt5$ s z to make a sort ( scoop by :i* ! drill+s may be scrap$ or hoi/$ out ( ! hole4 ,x is g5]ally advantage\s to p\r wat] into ! drill-hole :ile drill+ to keep ! drill f heat+4 ,p[] ,drills4--,:5 ! conditions are su* t use c be made ( !m1 x is ne>ly always pref]able to use p[] drills1 on acc\nt ( _! great] spe$ ( p5etration & great] economy ( "w4 ,p[] drills are work$ by direct /eam pressure1 or by compress$ air g5]at$ by /eam or wat] p[]1 & /or$ 9 receiv]s f :i* x is l$ to ! drills ?r\gh iron pipes4 ,a great v>iety ( =ms ( p[] drills are available = tunnel "w 9 rock1 b !y c ne>ly all be gr\p$ 9 "o ( two classes3 7#a7 ,p]cussion drills1 & 7#b7 ,rot>y drills4 ,p]cussion ,drills4--,! fir/ ,am]ican p]cussion drill 0 pat5t$ by ,mr4 ,j4 ,j4 ,c\* ( ,philadelphia1 ,p5n41 9 ,m>*1 #ahdi4 ,9 ,may ( ! same ye>1 ,mr4 ,joseph ,w4 ,f[le1 :o _h assi/$ ,mr4 ,c\* 9 develop+ 8 drill1 pat5t$ a p]cussion drill ( 8 own inv5tion4 ,! ,f[le drill 0 tak5 up & improv$ by ,mr4 ,*>les ,burleigh1 & 0 fir/ us$ on ! ,hoosac tunnel4 ,9 ,europe ,mr4 ,cav pat5t$ a p]cussion drill 9 ,france 9 ,octob]1 #ahea4 ,?is inv5tion 0 soon foll[$ by sev]al o!rs2 b x 0 n until ,sommeill]'s drill1 pat5t$ 9 #aheg & p]fect$ 9 #ahfa1 0 us$ on ! ,mont ,c5is tunnel1 t ! problem ( ! p]cussion drill 0 practically solv$ abroad4 ,s9ce ?is "t num]\s p]cussion drill pat5ts h be5 tak5 out 9 bo? ,am]ica & ,europe4 ,a p]cussion drill consi/s ( a cyl9d]1 9 :i* works a pi/on c>ry+ a long pi/on rod1 & :i* is support$ 9 su* a mann] t ! drill clamp$ to ! end ( ! pi/on rod alt]nately /rikes & is )drawn f ! rock z ! pi/on reciprocates back & =? 9 ! cyl9d]4 ,means are devis$ by :i* ! pi/on rod & drill turn slightly on _! axis aft] ea* /roke1 & also by :i* ! drill is f$ =w>d or advanc$ z ! dep? ( ! drill-hole increases4 ,! drills ( ?is type :i* are 9 mo/ common use 9 ,am]ica are ! ,+]soll-,s]geant & ! ,r&4 ,!re are v>i\s o!r makes 9 common use1 h[ev]1 :i* diff] f ! two nam$ & f ea* o!r *iefly 9 ! me?ods by :i* ! valve is op]at$4 ,all ( ^! drills "w ei!r ) direct /eam pressure or ) compress$ air4 ,workable p]cussion drills op]at$ by electricity are built1 b s f> !y d n seem to h be5 able to compete comm]cially ) ! old] =ms4 ,no attempt w be made "h to make a selection betwe5 ! v>i\s =ms ( p]cussion drills = tunnel "w1 & = ! diff]5ces 9 con/ruction & ! m]its claim$ = ea* ! read] is ref]r$ to ! mak]s ( ^! ma*9es4 ,all ( ! lead+ makes w give effici5t s]vice4 ,x goes almo/ )\t say+ t a good p]cussion drill %\ld op]ate ) little wa/e ( pressure1 & %\ld be compos$ ( b few p>ts1 :i* c be easily remov$ & *ang$4 ,drill ,m\nt+s4--,= tunnel "w ! g5]al ,european practice is to m\nt p[] drills ^u a c>riage mov+ on tracks 9 ord] t !y be easily )drawn dur+ ! fir+ ( bla/s4 ,connection is made ) ! /eam or compress$ air pipes by means ( flexible hose :i* c easily be atta*$ or deta*$ z ! drill advances or :5 x is mov$ = repairs or dur+ bla/s4 ,two1 f\r1 & sometimes m drills are m\nt$ & "w simultane\sly on a s+le c>riage4 ,9 ,am]ica x has be5 f\nd t column m\nt+s h be5 m successful = tunnel "w ?an any o!r =m4 ,! column m\nt+ made by ! ,+]soll-,s]geant ,drill ,co4 is %[n 9 ,fig4 #ab4 ,9 us+ ?is =m ( m\nt+ no tracks or o!r special app>atus is requir$2 x is n necess>y1 z is ! case ) ! c>riage m\nt+1 to remove ! dbris be=e resum+ op]ations1 b z soon z ! bla/+ has be5 f9i%$ & ! smoke has suffici5tly disappe>$ ! column c be set up & drill+ resum$4 ,illu/ration3 ,,fig4 #ab4--;,column ,m\nt+ = ,p]cussion ,drill3 ,+]soll-,s]geant ,drill ,co4 ,rot>y ,drills4--,rot>y drill+ ma*9es1 or m simply rot>y drills1 7 fir/ us$ 9 #aheg 9 ! ,mont ,c5is tunnel4 ,! advantages claim$ = rot>y drills 9 comp>ison ) p]cussion drills are3 7#a7 ,t less p[] is requir$ to drive ! drill1 & ! p[] is bett] utiliz$2 7#b7 once ! ma*9es "w easily !y d n require cont9ual repairs1 & 7#c7 9 driv+ holes ( l>ge size ! int]ior nucleus is tak5 away intact1 ?us r$uc+ "w & increas+ ! spe$ ( drill+4 ,rot>y drills are ext5sively us$ = geological1 m9+1 well-driv+1 & prospect+ purposes2 b !y are v seldom employ$ 9 tunnels 9 ,am]ica1 al?\gh successfully us$ = ?is purpose 9 ,europe4 ,! reason !y h n ga9$ m favor among ,am]ican tunnel build]s is due to "s ext5t p]haps to prejudice1 b *iefly to ! great co/ ( ! ma*9e z comp>$ ) p]cussion drills1 & to ! exp5se ( diamonds = repairs4 ,^? :o advocate ^! ma*9es = tunnel "w po9t out1 h[ev]1 t "u ord9>y usage ! diamonds h a v long life1--bor+s ( #gjj l94 ft4 be+ record$ )\t repairs to ! diamonds4 ,illu/ration3 ,,fig4 #ac4--,sket* ( ,diamond ,drill ,bit4 ,! =m ( rot>y drill us$ *iefly = prospect+ purposes is ! diamond drill4 ,?is ma*9e consi/s ( a holl[ cyl9drical bit hav+ a cutt+-edge ( diamonds1 :i* is revolv$ at ! rate ( f two hundr$ to f\r hundr$ revolutions p] m9ute by suitable ma*9]y op]at$ by /eam or compress$ air4 ,! diamonds are set 9 ! cutt+-edge ( ! bit s z to project outw>d f its annul> face & also slightly inside & outside ( its cyl9drical sides 7,fig4 #ac74 ,:5 ! drill rod ) ! bit atta*$ is rotat$ & f$ =w>d ! bit cuts an annul> hole into ! rock2 ! drill+s be+ remov$ f ! hole by a con/ant /ream ( wat] :i* is =c$ d[n ?r\gh ! holl[ drill rod & em]ges1 c>ry+ ! dbris ) x1 up ?r\gh ! n>r[ space betwe5 ! outside ( ! bit & ! walls ( ! hole4 ,!re are v>i\s makes ( diamond drills1 b !y all op]ate 9 ess5tially ! same mann]4 ,! rot>y drill pr9cipally employ$ 9 ,europe 9 tunnel+ is ! ,br&t4 ,! cutt+-edge ( ! ,br&t drill consi/s ( h>d5$ /eel tee?4 ,! bit is press$ aga9/ ! rock by hydraulic pressure1 & usually makes f sev5 to eight revolutions p] m9ute4 ,"s ( ! wat] :5 fre$ goes ?r\gh ! holl[ bit1 keep+ x cool1 & clean+ ! hole ( dbris4 ,a wat] pressure ( f #cjj to #dej lbs4 p] squ>e in* is requir$ to op]ate ^! drills4 ,rot>y rock-drills may be m\nt$ ei!r on c>riages or on columns = tunnel "w4 ,sev]al ma*9es h rec5tly be5 con/ruct$ = ! purpose ( break+ ! rock 9 tunnels )\t bla/+1 b !y did n meet ! approval ( tunnel eng9e]s4 ,"o ( ^! ma*9es is provid$ ) num]\s electric tor*es1 :i* are appli$ to ! rock at ! front4 ,by sudd5ly *ill+ ! rock ) a /ream ( cold wat] ! /one w crumble away4 ,ano!r ma*9e 0 te/$1 ) little success1 9 ! excavation = ! ,new ,gr& ,c5tral ,depot 9 ,new ,york4 ,on ! face ( ?is ma*9e !re is a multitude ( *ipp+ drills revolv+ on f\r arms & driv5 by air pressure4 ,!y attack ! rock & *ip x into fragm5ts1 :i* are c>ri$ away by an endless b&4 ,,explosives ,,& ,,bla/+4 ,:5 ! holes are once drill$1 ei!r by h& or p[] drills1 !y are *>g$ ) explosives4 ,! pr9cipal explosives employ$ 9 tunnel+ are gunp[d]1 nitroglyc]9e1 & dynamite4 ,gunp[d]4--,gunp[d] is compos$ ( *>coal1 sulphur1 & saltpet] 9 proportions v>y+ accord+ to ! quality ( ! p[d]4 ,= m9+ purposes ! composition employ$ is #fe saltpet]1 #ae sulphur1 & #bj *>coal4 ,x is a black granulat$ p[d] hav+ a specific gravity ( #a4e2 ! black color is giv5 by ! *>coal2 & ! gra9s h an angul> =m1 & v>y 9 size f 94 to 94 ,good bla/+ p[d] %\ld conta9 no f9e gra9s1 :i* may be detect$ by p\r+ "s ( ! p[d] ^u a %eet ( :ite pap]4 ,! =ce develop$ by ! explosion ( gunp[d] is n accurately kn[n2 x dep5ds ^u ! space 9 :i* x is conf9$4 ,diff]5t au?orities e/imate ! pressure at f #ae1jjj lbs4 p] sq4 94 9 loose bla/s to #bjj1jjj lbs4 p] sq4 94 9 gunn]y4 ,au?orities also diff] 9 op9ion z to ! "* ( ! gases develop$ by ! explosion ( gunp[d]1 a matt] ( vital conc]n to ! tunnel eng9e]1 s9ce !y are likely to affect ! heal? & com=t ( 8 workm54 ,x may be assum$ 9 a g5]al way1 h[ev]1 t ! oxyg5 ( ! saltpet] conv]ts ne>ly all ( ! c>bon ( ! *>coal into c>bon dioxide1 a portion ( :i* comb9es ) ! pota% ( ! saltpet] to =m c>bonate ( pota%1 ! rema9d] cont9u+ 9 ! =m ( gas4 ,! sulphur is conv]t$ into sulphuric acid1 & =ms a sulphate ( pota%1 :i* by reaction is decompos$ into hyposulphite & sulphide4 ,! nitrog5 ( ! saltpet] is almo/ entirely evolv$ 9 a free /ate2 & ! c>bon n hav+ be5 :olly burnt into c>bonic acid1 !re is a proportion ( c>bonic oxide4 ,nitroglyc]9e4--,nitroglyc]9e is "o ( ! mod]n explosives us$ z a sub/itute = gunp[d]4 ,x is a fluid produc$ by mix+ glyc]9e ) nitric & sulphuric acids2 x freezes at #da ,f41 & burns v quietly1 develop+ c>bonic acid1 nitrog51 oxyg51 & wat]4 ,by p]cussion or by ! explosion ( "s sub/ances1 su* z capsules ( gunp[d] or fulm9ate ( m]cury1 nitroglyc]9e produces a sudd5 explosion 9 :i* ab\t #abej volumes ( gases are produc$4 ,! pressure ( ^! gases has be5 calculat$ at #bf1jjj atmosph]es1 or #cbd1jjj lbs4 p] sq4 94 ,nitroglyc]9e explodes v easily by p]cussion 9 its normal /ate1 b ) great difficulty :5 froz52 h5ce1 9 ,am]ica1 at ! beg9n+ ( its use1 x 0 transport$ only 9 a froz5 /ate4 ,:5 dirty1 nitroglyc]9e und]goes a spontane\s decomposition accompani$ by ! developm5t ( gases & ! evolution ( heat1 :i*1 rea*+ #chh ,f41 causes x to explode4 ,not)/&+ ! enorm\s pressures :i* nitroglyc]9e develops1 x is v seldom us$ 9 its liquid /ate1 b is mix$ ) a granul> absorb5t e>? compos$ ( ! %ells ( diatoms4 ,! fluid und]goes no *emical *ange by be+ absorb$1 & explodes1 freezes1 & burns "u ! same conditions z 9 ! fluid /ate4 ,dynamite4--,! cr$it ( r5d]+ nitroglyc]9e available = ! purposes ( ! eng9e] by mix+ x ) a granul> absorb5t is due to ,alb]t ,nobel ( ,/ockholm1 ,sw$51 :o nam$ ! new mat]ial dynamite4 ,! nitroglyc]9e 9 dynamite loses v little ( its orig9al explosive p[]1 b is v mu* less easily explod$ by p]cussion1 & c be employ$ 9 horizontal z well z v]tical holes1 :i* 01 ( c\rse1 n possible 9 its liquid /ate4 ,dynamite mu/ conta9 at lea/ #ej ( nitroglyc]9e4 ,"s manufactur]s1 in/ead ( us+ diatomace\s e>?1 use o!r absorb5ts :i* develop gases ^u explosion & increase ! =ce ( ! explosion4 ,^! mixtures are class$ "u ! g5]al "n ( false dynamites4 ,a great _m v>ieties ( dynamite are manufactur$1 & ea* manufactur] usually makes a numb] ( grades to :i* he gives special names4 ,dynamite = railway "w1 tunnel+1 & m9+ conta9s ab\t #ej ( nitroglyc]9e2 = qu>ry+ ab\t #ce1 & = bla/+ s(t rocks ab\t #cj4 ,x is sold 9 cyl9drical c>tridges cov]$ ) pap]4 ,/orage ( ,explosives4--,9 driv+ tunnels ?r\gh rock l>ge quantities ( explosives mu/ be us$1 & x is necess>y to h "s safe place = /or+ !m4 ,9 _m ,/ates !re are special laws gov]n+ ! transportation & /orage ( explosives2 :]e !re is no regulation by law ! eng9e] %\ld take suitable precautions ( 8 own devis+4 ,x is be/ to build a special h\se or hut 9 "o ( ! mo/ conceal$ portions ( ! "w & away f ! tunnel1 & protect x ) a lightn+-rod & f fire4 ,/rict ord]s %\ld be giv5 to ! wat*man 9 *>ge n to all[ p]sons inside ) lamps or fire 9 any =m1 & smok+ %\ld be prohibit$4 ,! use ( hamm]s = op5+ ! boxes %\ld be prohibit$2 & dynamite1 gunp[d]1 & fulm9ate ( m]cury %\ld n be /or$ toge!r 9 ! same room4 ,a quantity ( dynamite = two or ?ree days' consumption may be /or$ ne> ! entrance ( ! tunnel 9 a lock$ box1 ! keys ( :i* are kept by ! =eman ( ! "w4 ,:5 dynamite has be5 froz5 ! eng9e] %\ld provide "s arrangem5t by :i* x may be heat$ to a temp]ature n exce$+ #abj ,f41 & absolutely =bid x be+ ?aw$ out on a /ove or by an op5 fire4 ,fuses4--,:5 gunp[d] is us$ 9 tunnel+ x is ignit$ by ! ,blick=d mat*4 ,?is mat*1 or fuse z x is m commonly call$1 consi/s ( a small rope ( y>n or cotton hav+ z a core a small cont9u\s ?read ( f9e gunp[d]4 ,to protect ! outside ( ! fuse f moi/ure x is coat$ ) t> or "s o!r imp]vi\s sub/ance4 ,^! fuses are s well made t !y burn v uni=mly at ! rate ( ab\t #a ft4 9 #bj seconds1 h5ce ! mom5t ( explosion c be pretty accurately fix$ be=eh&4 ,blick=d mat*es h ! objection = tunnel "w ( burn+ ) a bad odor1 especially :5 !y are coat$ ) t>1 & to rem$y ?is _m o!rs h be5 inv5t$4 ,^? ( ,rzika & ,franzl are ! be/ kn[n ( ^!4 ,! =m] has _m advantages1 b x burns too quickly1 ab\t #c ft4 p] second1 & is exp5sive2 ! latt] consi/s ( a small holl[ rope fill$ ) dynamite4 ,blick=d mat*es _c be us$ to explode dynamite1 ! use ( a c>tridge be+ requir$4 ,^! c>tridges are small copp] cyl9d]s conta9+ fulm9ate ( m]cury4 ,!y may be atta*$ to ! end ( ! ,blick=d mat*1 :i* be+ ignit$ ! sp>k travels along its l5g? until x rea*es ! copp] cyl9d]1 :]e x explodes ! fulm9ate ( m]cury1 :i* 9 turn explodes ! dynamite4 ,bla/s may also be fir$ by electricity1 :i*1 9 fact1 is ! mo/ common & ! pref]able me?od1 because sev]al bla/s c be fir$ simultane\sly1 & because ! curr5t is turn$ on at a great di/ance1 ?us af=d+ great] safety to ! workm54 ,! me?od ( electric fir+ g5]ally employ$ 9 ,am]ica is kn[n z ! connect+ s]ies me?od1 & consi/s 9 fir+ sev]al m9es simultane\sly4 ,! ends ( ! wires are scrap$ b>e1 & ! wire ( ! fir/ hole ( ! s]ies is twi/$ toge!r ) ! wire ( ! second hole1 & s on2 f9ally ! two odd wires ( ! fir/ & la/ holes are connect$ to two wires ( a s+le cable or to two sep>ate cables ext5d+ to "s safe place to :i* ! m5 c retreat4 ,"h ! two cable wires are connect$ by b9d+ screws to ! poles ( a batt]y1 or sometimes to a frictional electric ma*9e4 ,! curr5t passes ?r\gh ! wires1 mak+ a sp>k at ea* break1 & s fires ! fulm9ate ( m]cury1 :i* explodes ! dynamite4 ,simultane\s fir+ by electricity by utiliz+ ! unit$ /r5g? ( ! bla/s at ! same in/ant secures ab\t #aj great] effici5cy f ! explosives4 ,ano!r advantage ( electric fir+ is t 9 case ( a missfire ( any "o ( ! holes !re is slight possibility ( explosion aft]w>ds1 & ! place c be approa*$ at once to discov] ! cause4 ,tamp+4--,tamp+ is ! mat]ial plac$ 9 ! hole above ! explosive to prev5t ! gases ( explosion f escap+ into ! air4 ,tamp+ g5]ally consi/s ( clay4 ,:5 gunp[d] is us$ ! clay mu/ be well ramm$ ) a wood5 tool1 & pap]1 cotton1 or "s o!r dry mat]ial mu/ be plac$ betwe5 ! moi/ clay & ! p[d]4 ,:5 dynamite is us$ x is n necess>y to ram ! tamp+1 s9ce ! sudd5ness ( ! explosion %att]s ! rock be=e ! clay c be driv5 f ! hole4 ,a few exp]i5c$ m5 %\ld be appo9t$ to fire ! bla/s4 ,^! m5 %\ld give ample w>n+ previ\s to ! bla/ 9 ord] t all ma*9]y & tools :i* might be injur$ by fly+ fragm5ts may be remov$ out ( dang]1 & s t ! workm5 may seek safety4 ,:5 all is ready !y %\ld fire ! bla/s1 keep+ accurate c\nt ( ! explosions to ensure t no holes h miss$ fire1 & %\ld call ! workm5 back :5 all dang] is ov]4 ,9 case any hole has miss$ fire x %\ld be m>k$ by a r$ lamp or flag4 ,nature ( ,explosions4--,:5 ! explosives are ignit$ a sudd5 developm5t ( gases results1 produc+ a sudd5 & viol5t increase ( pressure1 usually accompani$ by a l\d report4 ,! en]gy ( ! explosion is ex]t$ 9 all directions 9 ! =m ( a sph]e hav+ its c5t] at ! po9t ( explosion1 & ! waves ( en]gy lose _! =ce z ! di/ance f ?is c5tral po9t increases4 ,! en]gy ( ! explosion at any po9t 9 ! sph]e ( en]gy is1 !re=e1 inv]sely proportional to ! di/ance ( ?is po9t f ! c5t] ( explosion4 ,9 ! vic9ity ( ! c5t] ( explosion ! gases h suffici5t p[] to de/roy ! =ce ( cohesion & %att] ! rock2 fur!r on1 z !y lose /r5g?1 !y only de/roy ! ela/icity ( ! mat]ial & produce cracks2 & /ill fur!r away !y only produce a %ock1 & d n affect ! mat]ial4 ,)9 ! sph]e ( en]gy !re are1 !re=e1 ?ree o!r conc5tric sph]es3 ! fir/ "o be+ :]e cohesion is de/roy$1 ! second :]e ela/icity is ov]come1 & ! ?ird :]e ! %ock is transmitt$ by ela/icity4 ,:5 ! latt] sph]e comes bel[ ! surface1 ! gases rema9 inside ! rock2 b :5 ! surface int]sects ei!r ( ! o!r two sph]es1 ! gases bl[ up ! rock1 =m+ a cone or crat]1 ^: apex is at ! po9t ( explosion1 & :i* is call$ ! bla/+-cone4 ,! l>g] ! bla/+-cone is1 ! great] is ! am\nt ( rock brok5 up2 & ! object ( ! eng9e] %\ld1 !re=e1 always be s to regulate ! dep? ( ! hole & ! quantity ( explosive z to secure ! l>ge/ possible bla/+ cone 9 ea* case4 ,exp]im5ts are requir$ to det]m9e ! mo/ effici5t dep? ( hole1 & quantity ( explosive to be employ$1 s9ce ^! diff] 9 diff]5t k9ds ( rock1 ) ! position ( ! rock /rata1 etc42 b 9 ord9>y practice1 ! dep?s ( ! holes are made f #b to #c ft4 9 ! head+ & upp] portion ( ! tunnel1 :5 drill$ by h&2 & f #f to #h ft4 :5 drill$ by p[] drills4 ,9 ! l[] portion ( ! pr(ile1 ! holes are made deep]1 f #c ft4 to #d ft4 :5 drill$ by h&1 & exce$+ #f ft4 :5 drill$ by p[]4 ,! di/ance ( ! holes ap>t %\ld be ab\t equal to ! diamet] ( ! bla/+-cone2 z a g5]al rule x is assum$ t ! base ( ! bla/+-cone has a diamet] equal to twice ! dep? ( ! hole4 ,! foll[+ table gives ! av]age numb] ( holes requir$ 9 ea* "p ( ! excavation = ! ,/4 ,go?>d tunnel 9 :i* ! head+ 0 excavat$ by ma*9e drills :ile ! o!r p>ts 7 excavat$ by h& drills3 ,,no4 ,,( ,,"p4#e ,,"n ,,( ,,"p4 ,,no4 ,,( ,,holes4 #a4 ,head+ #f to #i #b4 ,"r w+ ( head+ #c to #e #c4 ,left w+ ( head+ #c to #e #d4 ,%all[ tr5* ) core #b #e4 ,deep5+ ( tr5* to floor #f to #i #f4 ,n>r[ mass ( core to left #c #g4 ,great] mass ( core to left #f to #i #h4 ,culv]t #a -------- ,total section #cj to #dc #e ,! location ( ! p>ts numb]$ is %[n by ,fig4 #ad1 p4 #cf4 ,! quantity ( explosives requir$ = bla/+ dep5ds ^u ! quality ( ! rock1 s9ce ! =ce ( ! explosives mu/ ov]come ! cohesion ( ! rock1 :i* v>ies ) its nature1 & (t5 diff]s greatly 9 rocks ( ! same k9d & composition4 ,! quantity ( explosives requir$ to secure ! greate/ effici5cy 9 bla/+ any p>ticul> rock may be det]m9$ exp]im5tally1 b 9 practice x is usually d$uc$ by ! foll[+ rules3 7#a7 ,! bla/+ =ce is directly proportional to ! weight ( ! explosives us$1 & 7#b7 ! bulk ( ! bla/$ rock is proportional to ! cube ( ! dep? ( ! holes4 ,x is usually assum$1 also1 t ! explosive %\ld fill at lea/ "o-f\r? ! dep? ( ! hole4 ,! foll[+ table gives ! dep? ( holes & am\nt ( dynamite us$ at ea* advance 9 ! ,=t ,george ,tunnel illu/rat$ on page #ace4 ---------------------------------------- ---------------- ,,ord] ,,( ,,fir+4 ,,k9ds ,,( ,,dep?4 ,,*>ge4 ,,k9d ,,( ,,holes4 ,,dynamite4 ---------------------------------------- ---------------- ,b5* #a/ r\nd#d grad+ #c to #eej lbs4#dj climax ,holes #e b5* #i #f #de #dj #bnd r\nd#f trimm+ #c to #idb #dj ,head+ #c;d r\nd #h c5t] cut#i #ef #fj ,holes #d? r\nd#h side #h #dh #dj #e? r\nd#f dry #h #cf #dj ---------------------------------------- ---------------- ,,*apt] ,,iv4 ,,g5]al ,,me?ods ,,( ,,excavation3 ,,%afts3 ,,classification ,,( ,,tunnels4 ,a numb] ( diff]5t modes ( proc$ure are foll[$ 9 excavat+ tunnels1 & ea* ( ! m important ( ^! w be consid]$ 9 a sep>ate *apt]4 ,!re are1 h[ev]1 c]ta9 *>act]i/ics common to all ( ^! me?ods1 & ^! w be not$ briefly "h4 ,illu/ration3 ,,fig4 #ad4--;,diagram ,%[+ ,sequ5ce ( ,excavation = ,/4 ,go?>d ,tunnel4 ,illu/ration3 ,,fig4 #ae4--;,diagram ,%[+ ,mann] ( ,det]m9+ ,correspond5ce ( ,excavation to ,sectional ,pr(ile4 ,division ( ,section4--,x may be ass]t$ at ! outset t ! :ole area ( ! tunnel section is n ord9>ily excavat$ at "o "t1 b t x is remov$ 9 sections1 & z ea* section is excavat$ x is ?or\ghly timb]$ or /rutt$4 ,! ord] 9 :i* ^! diff]5t sections are excavat$ v>ies ) ! me?od ( excavation1 & x is cle>ly %[n = ea* me?od 9 succe$+ *apt]s4 ,z a s+le example to illu/rate ! proposition j made1 ! division ( ! section & ! sequ5ce ( excavation adopt$ at ! ,/4 ,go?>d tunnel is select$ 7,fig4 #ad74 ,! diff]5t p>ts ( ! section 7 excavat$ 9 ! ord] numb]$2 ! names giv5 to ea* "p1 & ! numb] ( holes employ$ 9 break+ x d[n1 are giv5 by ! table on page #ce4 ,:atev] me?od is employ$1 ! "w always beg9s by driv+ a head+1 :i* is ! mo/ difficult & exp5sive "p ( ! excavation4 ,all ! o!r op]ations requir$ 9 break+ d[n ! rema9d] ( ! tunnel section are usually designat$ by ! g5]al t]m ( enl>gem5t ( ! pr(ile4 ,! v>i\s op]ations ( excavation may1 !re=e1 be classifi$ ei!r z excavation ( ! head+ or enl>gem5t ( ! pr(ile4 ,excavation ( ! ,head+4--,!re is consid]able confusion among ! diff]5t au?orities reg>d+ ! exact def9ition ( ! t]m 8head+0 z x is us$ 9 tunnel "w4 ,"s au?orities call a small passage driv5 at ! top ( ! pr(ile a head+1 & a simil> passage driv5 at ! bottom ( ! pr(ile a drift2 o!rs call any passage driv5 p>allel to ! tunnel axis1 :e!r at ! top or at ! bottom ( ! pr(ile1 a drift2 & /ill o!rs give ! "n 8head+0 to all su* passages4 ,= ! sake ( di/9ctness ( t]m9ology x seems pref]able to call ! passage a head+ :5 x is locat$ at ! top ( ! pr(ile1 & a drift :5 x is locat$ ne> ! bottom4 ,head+s & drifts are driv5 9 advance ( ! g5]al excavation = ! foll[+ purposes3 7#a7 ,to fix correctly ! axis ( ! tunnel2 7#b7 to all[ ! "w to g on at diff]5t po9ts )\t ! gangs ( labor]s int]f]+ ) ea* o!r2 7#c7 to detect ! nature ( mat]ial to be dealt ) & to be ready 9 any cont+5cy to ov]come any tr\ble caus$ by a *ange 9 ! soil2 & 7#d7 to collect ! wat]4 ,! dim5sions ( head+s 9 actual practice v>y accord+ to ! nature ( ! soil ?r\gh :i* !y are driv54 ,z a g5]al rule !y %\ld n be less ?an #g ft4 9 height1 s z to all[ ! m5 to "w /&+1 & h room left = ! ro( /rutt+4 ,! wid? %\ld n be less ?an #f ft41 to all[ two m5 to "w at ! front1 & to give room = ! mat]ial c>s )\t int]f]+ ) ! wall /rutt+4 ,usually head+s are made #h ft4 wide4 ,! l5g? ( head+s 9 practice v>ies accord+ to circum/ances4 ,9 v long tunnels ?r\gh h>d rock ! head+s are sometimes excavat$ f #ajjj ft4 to #bjjj ft4 9 advance1 9 ord] t !y may meet z soon z possible & ! rang+ ( ! c5t] l9e be v]ifi$1 & s t z great an area ( rock z possible may be attack$ at ! same "t 9 ! "w ( enl>g+ ! pr(ile4 ,9 %ort tunnels1 :]e ! rang+ ( ! c5t] l9e is less liable to error1 %ort] head+s are employ$1 & 9 s(t soils !y are made %ort] & %ort] z ! cohesion ( ! soil decreases4 ,:5 ! mat]ial has too little cohesion to /& alone1 ! tops & sides ( ! head+ require to be support$ by /rutt+4 ,to prev5t cav+ at ! front ( ! head+1 ! face ( ! excavation is made incl9$1 ! incl9ation foll[+ z ne> z may be ! natural slope ( ! mat]ial4 ,enl>gem5t ( ! ,pr(ile4--,! enl>gem5t ( ! pr(ile is accompli%$ by excavat+ 9 succession sev]al small prisms p>allel to ! head+1 & its full l5g?1 :i* are s locat$ t z ea* "o is tak5 out ! cross-section ( ! orig9al head+ is enl>g$4 ,! numb]1 location1 & sequ5ce ( ^! prisms v>y 9 diff]5t me?ods ( excavation1 & are expla9$ 9 succe$+ *apt]s :]e ^! me?ods are describ$4 ,to direct ! excavation s z to keep x always )9 ! b\nd>ies ( ! adopt$ pr(ile1 ! eng9e] fir/ m>ks ! c5t] l9e on ! ro( ( ! head+ by wood5 or metal pegs1 or by "s o!r suitable means by :i* a plumb l9e may be susp5d$4 ,he next draws to a l>ge scale a pr(ile ( ! propos$ section2 & beg9n+ at ! top ( ! v]tical axis he draws horizontal l9es at regul> int]vals1 z %[n by ,fig4 #ae1 until !y int]sect ! b\nd>y l9es ( ! pr(ile1 & designates on ea* ( ^! l9es ! di/ance betwe5 ! v]tical axis & ! po9t :]e x int]sects ! pr(ile4 ,x is evid5t t if ! =eman ( excavation divides 8 plumb l9e 9 a mann] correspond+ to ! eng9e]'s draw+1 & !n measures horizontally & at "r angles to ! v]tical c5t] plane ( ! tunnel ! di/ance designat$ on ! horizontal l9es ( ! draw+1 he w h locat$ po9ts on ! pr(ile ( ! section1 or 9 o!r words h e/abli%$ ! limits ( excavation4 ,illu/ration3 ,,fig4 #af4--,pol> ,protractor = ,det]m9+ ,pr(ile ( ,excavat$ ,cross-,section4 ,9 ! excavation ( ! ,croton ,aqu$uct = ! wat] supply ( ,new ,york city1 an in/rum5t call$ a pol> protractor 0 us$ = det]m9+ ! location ( ! sectional pr(ile4 ,x 0 inv5t$ by ,mr4 ,alfr$ ,crav51 division eng9e] ( ! "w4 ,?is in/rum5t consi/s ( a circul> disk graduat$ to degrees1 & m\nt$ on a tripod 9 su* a mann] t x may be level$ up1 & also h a v]tical motion & a motion ab\t ! v]tical axis4 ,! con/ruction is %[n cle>ly by ,fig4 #af4 ,9 use ! device is m\nt$ ) its c5t] at ! axis ( ! tunnel4 ,a light wood5 measur+-rod tap]+ to a po9t1 %od ) brass & graduat$ to feet & hundr$?s ( a foot1 lies ^u ! wood5 arm or re/1 :i* revolves ^u ! face ( ! disk1 & slides out to a contact ) ! surface ( ! excavation at su* po9ts z are to be det]m9$4 ,if ! only in=mation desir$ is :e!r or n ! excavation is suffici5t or beyond ! e/abli%$ l9es1 ! rod is set to ! prop] radius1 & if x sw+s cle> ! fact is det]m9$4 ,if a true copy ( ! actual cross-section is desir$1 ! rod is br\ght into contact ) ! significant po9ts 9 ! cross-section1 & ! angles & di/ances are record$4 ,! g5]al me?od ( direct+ ! excavation 9 enl>g+ ! pr(ile by ref]r+ all po9ts ( ! pr(ile to ! v]tical axis is ! "o usually employ$ 9 tunnel+1 & gives good results4 ,x is consid]$ bett] 9 actual practice to h ! excavation exce$ ! pr(ile some:at ?an to h x fall %ort ( x1 s9ce ! voids c be m easily fill$ 9 ) riprap ?an ! encroa*+ rock c be excavat$ dur+ ! build+ ( ! masonry4 ,9 tunnels :]e /rutt+ is necess>y ! excavation mu/ be made en\gh l>g] ?an ! f9i%$ section to provide ! space = x4 ,9 s(t-gr\nd tunnels x is also usual to enl>ge ! excavation to all[ = ! probable slight s9k+ ( ! masonry4 ,! prop] all[ance = /rutt+ is usually left to ! judgm5t ( ! =eman ( excavation1 b ! all[ance = settlem5t mu/ be fix$ by ! eng9e]4 ,,%afts4 ,%afts are v]tical walls or passages sunk along ! l9e ( ! tunnel at "o or m po9ts betwe5 ! entrances1 to p]mit ! tunnel excavation to be attack$ at sev]al diff]5t po9ts at once1 ?us greatly r$uc+ ! "t requir$ = excavation4 ,%afts may be locat$ directly ov] ! c5t] ( ! tunnel or to "o side ( x1 &1 :ile usually v]tical1 are sometimes incl9$4 ,dur+ ! con/ruction ( ! tunnel ! %afts s]ve ! same purpose z ! entrances2 h5ce !y mu/ af=d a passageway = ! excavat$ mat]ials1 :i* h to be hoi/$ out1 & also = ! con/ruction tools & mat]ials :i* h to be l[]$ d[n !m4 ,!y mu/ also af=d a passageway = workm51 draft animals1 & = pipes = v5tilation1 wat]1 compress$ air1 etc4 ,! "* ( ?is traffic indicates ! dim5sions requir$1 b ^! dep5d also ^u ! me?od ( hoi/+ employ$4 ,?us1 :5 a w9dlass or horse g9 is us$1 & ! mat]ials are hoi/$ 9 buckets ( small dim5sions1 ! dim5sions ( ! %aft may also be small2 b :5 /eam elevators are employ$1 & ! mat]ial is c>ri$ on c>s run on to ! plat=m ( ! elevator1 l>ge dim5sions mu/ be giv5 to ! %aft4 ,g5]ally ! p>ts ( ! %aft us$ = diff]5t purposes are sep>at$ by p>titions4 ,! elevator = workm5 & ! v>i\s pipes are plac$ 9 "o comp>tm5t1 :ile ! elevator = hoi/+ ! excavat$ mat]ial & l[]+ con/ruction mat]ial is plac$ 9 ano!r4 ,%afts may be ei!r tempor>y or p]man5t4 ,!y are tempor>y :5 !y are fill$ 9 aft] ! tunnel is complet$1 & p]man5t :5 !y are left op5 to supply v5tilation to ! tunnel4 ,p]man5t %afts are usually made circul>1 & l9$ ) brick1 unless excavat$ 9 v h>d & durable rock4 ,:5 sunk = tempor>y use only1 %afts are usually made rectangul> ) ! great] dim5sion transv]se to ! tunnel4 ,!y are /rutt$ ) timb]4 ,a pump is g5]ally locat$ at ! bottom ( ! %aft to collect ! wat] :i* seeps 9 f ! sides ( ! %aft & f ! tunnel excavation4 ,! dim5sions ( ?is pump w ( c\rse v>y ) ! am\nt ( wat] enc\nt]$1 z w also ! capacity ( ! pump = =c+ x up & out ( ! %aft1 :i* has always to be kept dry4 ,! majority ( eng9e]s pref] to s9k %afts directly ov] ! c5t] l9e ( ! tunnel4 ,side %afts are employ$ *iefly by ,fr5* eng9e]s4 ,! *ief advantage ( ! =m] me?od is ! great facility :i* x af=ds = hoi/+ out ! mat]ials1 :ile 9 favor ( ! latt] me?od is ! non-int]f]5ce ( ! %aft ) ! op]ations inside ! tunnel4 ,7 x n t ! side %aft requires ! introduction ( a transv]se gall]y connect+ x ) ! tunnel1 x w\ld be on ! :ole sup]ior to ! c5t] %aft2 b ! side gall]y necessitates turn+ ! c>s at "r angles1 & consequ5tly ! use ( a v %>p curve or a turntable to rea* ! %aft bottom1 :i* is a disadvantage t may outweigh its advantages 9 "s o!r respects4 ,x is impossible to /ate absolutely :i* ( ^! me?ods ( locat+ %afts is ! be/2 bo? pres5t advantages & disadvantages1 & ! use ( "o or ! o!r is usually det]m9$ m by ! local conditions ?an by any g5]al sup]iority ( ei!r4 ,:5 side %afts are employ$ !y are sometimes made incl9$ in/ead ( v]tical4 ,?is =m is us$ :5 ! dep? ( ! %aft is small4 ,by x ! haul+ is greatly simplifi$1 s9ce ! c>s load$ at ! front ) excavat$ mat]ial c be haul$ directly out ( ! %aft & to ! dump+-place1 surm\nt+ ! incl9$ %aft by means ( cont9u\s cables4 ,! %ort gall]ies connect+ ! side %afts ) ! tunnel prop] usually h a small] section ?an ! tunnel1 b are excavat$ 9 exactly ! same mann]4 ,ano!r =m ( side %aft sometimes us$ is "o rea*+ to ! surface :5 ! tunnel runs close to ! side ( cliff1 z is ! case ) "s ( ! ,alp9e railway tunnels4 ,,classification ,,( ,,tunnels4 ,tunnels are classifi$ 9 v>i\s ways1 b ! mo/ logical me?od w\ld appe> to be a gr\p+ accord+ to ! quality ( ! mat]ial ?r\gh :i* !y are driv52 & ?is me?od w be adopt$ "h4 ,by ?is me?od we h fir/ ! foll[+ g5]al classification3 7#a7 ,tunnels 9 h>d rock2 7#b7 tunnels 9 ord9>y loose soil2 7#c7 tunnels 9 quicks&2 7#d7 op5-cut tunnels2 & 7#e7 subm>9e tunnels4 ,x is h>dly necess>y to say t ?is classification1 l all o!rs1 is simply an arbitr>y arrangem5t adopt$ = ! sake ( ord] & conv5i5ce 9 treat+ ! subject4 ,tunnels 9 ,h>d ,rock4--,) ! num]\s labor-sav+ me?ods & ma*9es n[ available1 h>d rock is p]haps ! safe/ & easie/ ( all mat]ials ?r\gh :i* to drive a tunnel4 ,tunnels ?r\gh h>d rock may be excavat$1 ei!r by a drift or by a head+4 ,! diff]5ce dep5ds ^u :e!r ! advance gall]y is locat$ close to ! floor or ne> ! s(fit ( ! section4 ,tunnels 9 ,loose ,soils4--,9 driv+ tunnels ?r\gh loose soils _m diff]5t me?ods h be5 devis$1 :i* may be gr\p$ z foll[s3 7#a7 ,tunnels excavat$ at ! s(fit--,belgian me?od2 7#b7 tunnels excavat$ along ! p]imet]--,g]man me?od2 7#c7 tunnels excavat$ 9 ! :ole section--,engli%1 ,au/rian & ,am]ican me?ods2 7#d7 tunnels excavat$ 9 two halves indep5d5t ( ea* o!r--,italian me?od4 7#a7 ,excavat+ ! tunnel by beg9n+ at ! s(fit ( ! section1 or by ! ,belgian me?od1 is ! me?od ( tunnel+ 9 loose soils mo/ commonly employ$ 9 ,europe at ! pres5t "t4 ,x consi/s 9 excavat+ ! s(fit ( ! section fir/2 !n build+ ! ar*1 :i* is support$ ^u ! unexcavat$ gr\nd2 & f9ally 9 excavat+ ! l[] portion ( ! section1 & build+ ! side walls & inv]t4 7#b7 ,9 excavat+ tunnels along ! p]imet] an annul> excavation is made1 foll[+ closely ! outl9e ( ! sectional pr(ile 9 :i* ! l9+ masonry is built1 aft] :i* ! c5t] core is excavat$4 ,9 ! ,g]man me?od two drifts are op5$ at ea* side ( ! tunnel ne> ! bottom4 ,o!r drifts are excavat$1 "o above ! o!r1 on ea* side to ext5d or height5 ! fir/ two until all ! p]imet] is op5 except across ! bottom4 ,! masonry l9+ is !n built f ! bottom upw>ds on ea* side to ! cr[n ( ! ar*1 & !n ! c5t] core is remov$ & ! inv]t is built4 7#c7 ,?is me?od1 z its "n implies1 consi/s 9 tak+ out %ort l5g?s ( ! :ole sectional pr(ile be=e beg9n+ ! build+ ( ! masonry4 ,9 ! ,engli% me?od ! inv]t is built fir/1 !n ! side walls1 & f9ally ! ar*4 ,! excavators & masons "w alt]nately4 ,! ,au/rian me?od diff]s 9 two p>ticul>s f ! ,engli%3 ! l5g? ( section op5$ is made great en\gh to all[ ! excavators to cont9ue "w ahead ( ! masons1 & ! side walls & ro( are built be=e ! inv]t4 ,9 ! ,am]ican me?od ! :ole section ( ! tunnel is op5 at once3 excavators & masons "w simultane\sly1 b a v l>ge quantity ( timb]+ is requir$4 7#d7 ,! ,italian me?od is v seldom employ$ on acc\nt ( its exp5siv5ess1 b x c (t5 be us$ :]e ! o!r me?ods fail4 ,x consi/s 9 excavat+ ! l[] half ( ! section1 & build+ ! inv]t & side walls1 & !n fill+ ! space betwe5 ! walls 9 aga9 except = a n>r[ passageway = ! c>s2 next ! upp] "p ( ! section is excavat$1 z 9 ! ,belgian me?od1 & ! ar* is built2 & f9ally ! soil 9 ! l[] "p is p]man5tly remov$4 ,tunnels 9 ,quicks&4--,tunnels ?r\gh quicks& are driv5 by "o ( ! ord9>y s(t-gr\nd me?ods aft] dra9+ away ! wat]1 or else z subm>9e tunnels4 ,op5-,cut ,tunnels4--,op5-cut tunnels are ^? driv5 at su* a small dep? "u ! surface t x is m conv5i5t to excavate an op5 cut1 build ! tunnel masonry inside x1 & !n refill ! op5 spaces1 ?an x is to c>ry on ! "w entirely und]gr\nd4 ,9 firm soils ! usual mode ( op]ation is to excavate fir/ two p>allel tr5*es = ! side walls1 !n remove ! core1 & build ! ar* & ! inv]t4 ,9 un/able soils1 s9ce ! inv]t mu/ be built fir/1 x is usual to op5 up a s+le wide tr5*4 ,9 infrequ5t cases :]e a tunnel is desir$ 9 a place :i* is to be fill$ 91 ! masonry is built z a surface /ructure1 :i* 9 due "t is cov]$4 ,subm>9e ,tunnels4--,! mode ( proc$ure foll[$ 9 excavat+ subm>9e tunnels dep5ds ^u :e!r ! mat]ial p5etrat$ is p]vi\s or imp]vi\s to wat]4 ,9 imp]vi\s mat]ial any ( ! ord9>y me?ods ( tunnel+ f\nd suitable may be employ$4 ,9 p]vi\s mat]ial ! excavation may be accompli%$ ei!r by means ( compress$ air to keep ! wat] out ( ! excavation1 or by means ( a %ield clos+ ! front ( ! excavation1 or by a comb9ation ( ^! two me?ods4 ,tunnels on ! riv] b$ are built by means ( c(f] dams :i* inclose alt]nate portions ( ! "w1 by s9k+ a cont9u\s s]ies ( pneumatic caissons & op5+ communication betwe5 !m1 & by s9k+ ! tunnel 9 sections con/ruct$ on l&4 ,9 h>d rock4 ,by drifts4 ,by a head+4 ,by upp] half3 ! ar* is built ,belgian me?od4 be=e ! side walls4 ,by ! p]imet]3 excavat$ & l9$ be=e ! c5tral ,g]man me?od4 nucleus is remov$4 ,9 loose soil4,by :ole section3 ,engli% me?od4 ! l9+ beg9s aft],au/rian me?od4 ! :ole section is ,am]ican me?od4 excavat$4 ,by halves3 ! l[] half is excavat$ & l9$1 ,italian me?od4 foll[$ by ! "w ( ! upp] half4 ,,me?ods ,,( ,,excavat+,9 quicks&4 ,,tunnels4 ,9 resi/ant soils4 ,by two lat]al n>r[ tr5*es4 ,op5-cut tunnels4 ,9 loose soils4 ,by "o v l>ge tr5*4 ,built up4 ,by slices4 ,at great dep?s "u ,by any me?od4 ! riv] b$4 ,by %ield4 ,at small dep?s ,by compress$ "u ! riv] air4 ,subm>9e b$4 ,by %ield & tunnels4 compress$ air4 ,by c(f] dams4 ,by pneumatic ,on ! riv] b$4 caissons4 ,by built-up sections4 ,! above diagram gives 9 compact =m ! classification ( tunnels accord+ to mat]ials p5etrat$ & me?ods ( excavation adopt$1 :i* h be5 describ$ m fully 9 ! succe$+ p>agraphs4 ,x may be not$ "h aga9 t ?is is a purely arbitr>y classification1 & s]ves mo/ly z a conv5i5ce 9 discuss+ ! diff]5t classes ( tunnels )\t confusion4 ,,*apt] ,v4 ,,me?ods ,,( ,,timb]+ ,,or ,,/rutt+ ,,tunnels4 ,! purpose ( timb]+ or /rutt+ 9 tunnel "w is to prev5t ! cav+-9 ( ! ro( & side walls ( ! excavation previ\s to ! con/ruction ( ! l9+4 ,z ! /rutt+ has to resi/ all ! pressures develop$ 9 ! ro( & side walls1 :i* may be exce$+ly tr\blesome & ( great int5sity 9 loose soils1 its design & erection call = p>ticul> c>e4 ,! me?od ( /rutt+ adopt$ dep5ds ^u ! me?od ( excavation employ$2 b 9 e case ! problem is n only to build x /rong en\gh to )/& ! pressures develop$1 b to d ?is z economically z possible1 & ) z little h9drance z may be to ! "w :i* is go+ on simultane\sly & :i* w come lat]4 ,only ! latt] g5]al problems ( /rutt+ peculi> to all me?ods ( tunnel "w w be consid]$ "h4 ,= ?is consid]ation /rutt+ may be classifi$ accord+ to ! mat]ial ( :i* x is built1 "u ! heads ( timb] /ructures & iron /ructures4 ,illu/ration3 ,,fig4 #ag4--;,jo9+ ,tunnel ,/ruts by ,halv+4 ,illu/ration3 ,,fig4 #ah4--,r\nd ,timb] ,po/ & ,cap ,be>+4 ,,timb] ,,/rutt+4 ,timb] is ne>ly always employ$ = /rutt+ 9 tunnel "w4 ,s long z x has ! requisite /r5g?1 any k9d ( timb] is suitable = /rutt+1 s9ce1 x be+ only tempor>ily employ$1 its durability is a matt] ( slight importance4 ,timb] ) good ela/ic prop]ties1 l p9e or spruce1 is pref]ably *os51 s9ce x yields gradually "u /ress1 ?us w>n+ ! eng9e] ( ! approa* ( dang]2 :ile oak & o!r /rong timb]s resi/ until ! la/ mom5t1 & !n yield sudd5ly "u ! break+ load4 ,s(t woods1 moreov]1 are usually light] 9 weight ?an h>d woods1 :i* is a consid]able advantage :]e s mu* h&l+ is requir$ 9 a re/rict$ space4 ,r\nd timb]s are g5]ally employ$1 s9ce !y are less exp5sive1 & q z satisfactory 9 o!r respects z saw$ timb]s4 ,9 ! ,engli% & ,au/rian me?ods ( /rutt+1 :i* are describ$ fur!r on1 a few ( ! pr9cipal /ruts are ( saw$ timb]s4 ,! v>i\s timb]s ( ! /rutt+ are seldom atta*$ by fram$ jo9ts1 b w$ges are us$ to give !m ! necess>y be>+ aga9/ ea* o!r4 ,:]e fram$ jo9ts are employ$ !y are made ( ! simple/ =m usually by halv+ ! jo9+ timb]s1 z %[n by ,fig4 #ag4 ,fig4 #ah %[s a =m ( jo9t us$ :]e r\nd po/s c>ry beams ( simil> %ape4 ,! reason :y x is possible to d away ) jo9t$ connections to su* a great ext5t1 is t ! /ra9s :i* ! timb]s h to resi/ are ei!r compressive or b5d+ /ra9s1 & because ! timb]s are s %ort t !y d n require to be splic$4 ,/rutt+ ( ,head+s4--,! me?od ( /rutt+ ! head+ t is employ$ dep5ds ^u ! mat]ial ?r\gh :i* ! head+ is driv54 ,9 solid rock /rutt+ may n be requir$ at all1 or only = ! purpose ( prev5t+ ! fall ( loose blocks f ! ro(1 !n v]tical props are erect$ :]e requir$1 or horizontal beams are ins]t$ into ! side walls1 z %[n by ,fig4 #ai4 ,^! horizontal beams may be us$ s+ly at dang]\s places1 or !y may be plac$ f #b ft4 to #c ft4 ap>t all along ! head+4 ,9 ! latt] case !y usually c>ry a lagg+ ( planks1 :i* may be plac$ at int]vals or close toge!r1 & fill$ above ) /one 9 case ! ro( ( ! excavation is v un/able4 ,planks us$ 9 ?is mann] are usually call$ pol+-bo>ds4 ,:]e ! side walls z well z ! ro( require support1 v]tical side po/s are employ$ to c>ry ! ro( beams1 z %[n by ,fig4 #bj2 &1 :5 necess>y1 pol+-bo>ds are ins]t$ betwe5 ^! po/s & ! walls ( ! excavation4 ,illu/ration3 ,,fig4 #ai4--;,ceil+ ,/rutt+ = ,tunnel ,ro(s4 ,illu/ration3 ,,fig4 #bj4--;,ceil+ ,/rutt+ ) ,side ,po/ ,supports4 ,illu/ration3 ,,fig4 #ba4--,sill1 ,side ,po/ & ,cap ,cross ,frame ,/rutt+4 ,illu/ration3 ,,fig4 #bb4--,re9=c$ ,cross ,frame ,/rutt+ = ,trea*]\s ,mat]ials4 ,frame ,/rutt+4--,9 v loose soils n only ! ro( & side walls1 b also ! floor ( ! head+ require /rutt+4 ,9 ^! cases frame /rutt+ is employ$1 z %[n by ,fig4 #ba4 ,x consi/s simply ( a rectangul> frame2 at ! top !re is a cr[n b> support$ by two v]tical side po/s sett+ on a sill laid across ! bottom ( ! head+4 ,^! frames are spac$ at close int]vals1 & c>ry longitud9al planks or pol+-bo>ds4 ,! sill ( ! frame is sometimes omitt$ :5 ! soil is /able en\gh to p]mit x1 & 9 its place wood5 foot+ blocks are sub/itut$ to c>ry ! side po/s4 ,9 soils :]e ! pressures are great en\gh to b5d ! cr[n b>1 a second>y frame is employ$1 z %[n by ,fig4 #bb1 ! two incl9$ ro( memb]s1 or raft]s1 ( :i* support ! cr[n b> at ! c5t]4 ,illu/ration3 ,,fig4 #bc4--,longitud9al ,pol+-,bo>d ,sy/em ( ,ro( ,/rutt+4 ,illu/ration3 ,,fig4 #bd4--,transv]se ,pol+-,bo>d ,sy/em ( ,ro( ,/rutt+4 ,x is ! m common practice 9 driv+ head+s ?r\gh s(t soils to use incl9$ pol+-bo>ds to support ! ro(4 ,fig4 #bc %[s "o me?od ( do+ ?is4 ,! me?od ( op]ation is z foll[s3 ,assum+ ! pol+-bo>ds a & b to be 9 place1 & support$ by ! frames ,a1 ,b1 ,c1 z %[n1 ! fir/ /ep 9 cont9uation ( ! "w is to ins]t ! pol+-bo>d c ov] ! cr[n b> ( frame ,c1 & "u ! block m4 ,excavation is !n begun at ! top1 & z fa/ z ! soil is remov$ ahead ( x ! pol+-bo>d c is driv5 ahead until its re> end only slightly ov]hangs ! cr[n b> ( frame ,c4 ,! rema9d] ( ! face ( ! head+ is !n excavat$ ne>ly to ! front end ( ! pol+-bo>d c1 & ano!r frame is set up4 ,by a succession ( ^! op]ations ! head+ is advanc$4 ,! pol+-bo>ds at ! sides ( ! head+ are plac$ 9 a simil> mann] to ! ro( pol+-bo>ds4 ,a second me?od ( us+ incl9$ pol+-bo>ds is %[n by ,fig4 #bd4 ,"h ! pol+-bo>ds run transv]sely1 & are support$ by ! arrangem5t ( timb]+ %[n4 ,! *ief advantage ( us+ ^! incl9$ pol+-bo>ds1 p>ticul>ly 9 ! mann] %[n by ,fig4 #bc1 is t ! excavators "w "u cov] at all times1 & are ?us safe f fall+ fragm5ts or sudd5 cav+s4 ,box ,/rutt+4--,9 v trea*]\s soils1 su* z quicks&1 peat1 & lam9at$ clay1 box /rutt+ is commonly employ$4 ,! me?od ( build+ ?is /rutt+ is to set up at ! face ( ! "w a rectangul> frame1 & use x z a guide 9 driv+ a lagg+ or box+ ( horizontal planks into ! s(t soil ahead4 ,^! planks h %>p edges1 & are driv5 to a di/ance ( #b ft4 or #c ft4 into ! face ( ! head+1 s z to inclose a rectangul> body ( e>?4 ,?is e>? is excavat$ ne>ly to ! ends ( ! planks1 & !n ano!r frame is ins]t$ close up aga9/ ! new face ( ! excavation1 :i* supports ! planks s t ! rema9d] ( ! e>? includ$ by !m may be remov$4 ,^! two frames1 ) _! plank lagg+1 con/itute a 8box20 & a s]ies ( ^! boxes1 "o succe$+ ano!r1 =m ! /rutt+ ( ! head+4 ,/rutt+ ! ,face4--,9 "s cases x is f\nd necess>y to /rut ! face ( ! head+ 9 ord] to prev5t x f cav+ 94 ,?is is g5]ally done by sett+ plank v]tically1 & brac+ !m up by means ( incl9$ props ^: feet abut aga9/ ! sill ( ! ne>e/ cross frame4 ,?is /rutt+ is erect$ :ile ! workm5 are plac+ ! side & ro( /rutt+1 & is remov$ to p]mit excavation4 ,full ,section ,timb] ,/rutt+4--,= /rutt+ ! full section two =ms ( timb]+ are employ$1 kn[n z ! polygonal sy/em & ! longitud9al sy/em4 ,longitud9al /rutt+ consi/s ( a timb] /ructure s arrang$ z to h all ! pr9cipal memb]s support+ ! pol+-bo>ds p>allel to ! axis ( ! tunnel4 ,?is sy/em ( /rutt+ is peculi> to ! ,engli% me?od ( tunnel+4 ,! longitud9al timb]s re/ on ?is f9i%$ masonry at "o end1 & are c>ri$ on a cross frame or by props at ! o!r end4 ,at int]m$iate po9ts ! longitud9als are brac$ ap>t by /ruts 9 planes transv]se to ! tunnel axis4 ,?is con/ruction makes a v /rong /rutt+ framework1 s9ce ! transv]se /ruts act z ar* ribs to /iff5 ! longitud9als2 b ! use ( transv]se pol+-bo>ds requires ! excavation ( a l>g] cross-section ?an is necess>y :5 longitud9al pol+-bo>ds are employ$1 & ?is increases ! co/ bo? = ! am\nt ( e>? excavat$ & ! great] quantity ( fill+ requir$4 ,9 polygonal /rutt+ ! ma9 memb]s are 9 a plane normal to ! axis ( ! tunnel4 ,!y =m a polygon ^: sides foll[ closely ! sectional pr(ile ( ! excavation4 ,^! polygonal frames are plac$ at m or less %ort int]vals ap>t1 & are brac$ toge!r by %ort longitud9al /ruts ly+ close to ! sides ( ! excavation1 & runn+ f "o frame to ! next1 & also by long] longitud9al memb]s :i* ext5d ov] sev]al frames4 ,! polygonal sy/em ( /rutt+ is peculi> to ! ,au/rian me?od ( tunnel+1 & is fully describ$ 9 a succe$+ *apt]4 ,"o ( its di/9ctive *>act]i/ics is t ! pol+-bo>ds are ins]t$ p>allel to ! tunnel axis4 ,polygonal /rutt+ is g5]ally held to be /rong] ?an longitud9al /rutt+ "u uni=m loads1 b x is m liable to di/ortion :5 ! loads are unsymmetrical4 ,illu/ration3 ,,fig4 #be4--,%aft ) ,s+le ,transv]se ,/rutt+4 ,illu/ration3 ,,fig4 #bf4--,rectangul> ,frame ,/rutt+ = ,%afts4 ,illu/ration3 ,,fig4 #bg4--,re9=c$ ,rectangul> ,frame ,/rutt+ = ,%afts 9 ,trea*]\s ,mat]ials4 ,/rutt+ ( ,%afts4--,tunnel %afts are /rutt$ bo? to prev5t ! cav+-9 ( ! sides & to divide !m into comp>tm5ts4 ,:5 ! mat]ial p5etrat$ is v compact1 & cav+ is n likely1 a s+le s]ies ( transv]se /ruts1 "o above ! o!r1 runn+ f ! top to ! bottom ( ! %aft1 z %[n by ,fig4 #be1 is us$ to divide x into two comp>tm5ts4 ,9 s(t] mat]ial1 :]e ! sides ( ! %aft require support1 ,fig4 #bf %[s a =m ( /rutt+ commonly employ$4 ,x consi/s ( v]tical corn] po/s brac$ ap>t at int]vals by f\r horizontal /ruts plac$ close to ! walls ( ! %aft4 ,! long] side /ruts are also brac$ ap>t at ! c5t] by a middle /rut :i* divides ! %aft into two comp>tm5ts4 ,a lagg+ ( v]tical plank is plac$ betwe5 ! walls ( ! %aft & ! horizontal side /ruts4 ,9 v loose soils ! =m ( /rutt+ %[n by ,fig4 #bg is employ$4 ,?is is practically ! same con/ruction z is %[n by ,fig4 #bf1 ) ! addition ( an int]ior polygonal horizontal brac+ 9 ea* half ( ! %aft4 ,ref]r+ to ,fig4 #bg1 ! timb]s a1 a1 etc41 are v]tical & cont9u\s f ! top to ! bottom ( ! %aft2 & ! horizontal timb]s1 b1 b1 etc41 are spac$ at m or less close int]vals v]tically4 ,! lagg+ planks may be laid ) spaces betwe5 !m1 or close toge!r1 or1 9 case ( v loose mat]ial1 ) _! edges ov]lapp+4 ,! mann] ( con/ruct+ ! /rutt+ is also gov]n$ by ! /ability ( ! soil4 ,9 firm soils x is possible to s9k ! %aft q a dep? )\t timb]+1 & ! timb]+ c be erect$ 9 sections ( consid]able l5g?1 :i* is always an advantage1 b 9 loose soils ! timb]+ has to foll[ closely ! excavation4 ,! solid wall %aft /rutt+s :i* h be5 describ$ are discont9u$ at ! po9t :]e ! %aft int]sects ! tunnel excavation2 & f ?is po9t to ! floor ( ! tunnel an op5 timb]+ is employ$1 ^: only duty is to support ! weight ( ! solid /rutt+ above4 ,?is timb]+ is made 9 v>i\s =ms1 b ! mo/ common is a timb] truss or ar* con/ruction :i* spans ! tunnel section4 ,quantity ( ,timb]4--,! quantity ( timb] employ$ 9 /rutt+ a tunnel v>ies ) ! "* ( ! mat]ial ?r\gh :i* ! tunnel is excavat$3 x is small = solid-rock tunnels1 & l>ge = s(t-gr\nd tunnels4 ,9 ! ,belgian me?od ( excavation a small] quantity ( timb] is us$ ?an 9 any ( ! o!r ord9>y me?ods4 ,= s+le-track tunnels excavat$ by ?is me?od !re w be ne$$ on an av]age ab\t #c to #c cu4 yds4 ( timb] p] l9eal foot ( tunnel4 ,practical exp]i5ce %[s t ab\t f\r-fif?s ( ! timb] once us$ c be employ$ = ! second "t4 ,9 any ( ! me?ods 9 :i* ! :ole tunnel section is excavat$ at once1 ! av]age am\nt ( timb] requir$ p] l9eal foot is ab\t #h4g cu4 yds4 ,( ?is am\nt ab\t two-?irds c be us$ a second "t4 ,9 ! ,italian me?od1 9 :i* ! upp] half & ! l[] half are excavat$ sep>ately1 ab\t #e cu4 yds4 ( timb] are requir$ p] l9eal foot ( tunnel1 ab\t "o-half ( :i* c be employ$ a second "t4 ,= quicks& tunnels ! am\nt ( timb]+ requir$ p] l9eal foot v>ies f #c to #e cubic yds4 ,%aft /rutt+ requires f #a to #a cu4 yds4 ( timb] p] l9eal foot4 ,dim5sions ( ,timb]4--,! dim5sions ( ! pr9cipal memb]s compos+ ! /rutt+ ( head+s1 full section1 & %afts1 are giv5 9 ,table ,i4 ,! planks us$ = lagg+ or ! pol+-bo>ds are usually f #d ins4 to #f ins4 wide1 ) a l5g? dep5d+ ^u ! me?od ( /rutt+ employ$4 ,,table ,i4 ,%[+ ,sizes ( ,v>i\s ,timb]s ,us$ 9 ,/rutt+ ,tunnels ,driv5 ,?r\gh ,diff]5t ,mat]ials4 ---------------------------------------- -------------------------- ,,rock4 ,,s(t ,,soils4 ------------------------------ ,h>d4,s(t4,compact4,loose4 ,v loose4 ------------------------------ ins4 ins4 ins4 ins4 ins4 ,head+s3 ,cap-pieces & v]tical /ruts #f #h #aj #ab #ad ,sills #h #aj #ab ,/ruts #e #e #f #g #h ,di/ance ap>t ( ! frames 9 feet #f #d4e #c #b4f #b4f ,/rutt+ ( ! tunnel1 longitud9al /rutt+3 ,cr[n b>s #ab #ad #ad ,props v]tical or incl9$ support+ ! cr[n b>s #aj #ab #ad ,sills #h #h #aj ,cap-pieces or saddles #aj #ab #ad ,/ruts to /iff5 ! /ructure #f #h #aj ,di/ance ap>t ( ! frames 79 feet7 #d4e #d #c ,polygonal /rutt+3 ,cap-pieces & cont\r pieces #h #aj #ab #ad #af ,v]tical /ruts on top #aj #ab #ad #af #ah ,v]tical /ruts bel[ #ab #ad #af #bj #bd ,int]m$iate sills #ab #ad #af #bj #bd ,l[] sills #ab #af #ah ,rak+ props #aj #aj #aj #ab #ab ,di/ance ap>t ( ! frames 79 feet7 #f #d4e #d #c #c ,%afts3 ,horizontal beams =m+ ! frame #h #h #aj #ab #ad ,transv]se beams #h #h #h #aj #ab ,v]tical /ruts betwe5 ! frames #h #h #aj #ab #ab ,/ruts to ren=ce ! frame #f #h #h #h ,di/ance ap>t ( ! /rutt+ 79 feet7 #f #d4e #d #c #b4f ---------------------------------------- ----------------------- ,,iron ,,/rutt+4 ,9 #ahfb ,mr4 ,rziha employ$ old iron railway rails = /rutt+ ! ,na5s5 tunnel1 & 8 example 0 successfully foll[$ 9 sev]al tunnels built lat] :]e timb] 0 sc>ce & exp5sive4 ,! advantages :i* iron /rutt+ is claim$ to possess ov] ! m common wood5 /ructure are3 its great] /r5g?2 ! small] am\nt ( space :i* x takes up2 & ! fact t x does n we> out1 & may1 !re=e1 be us$ ov] & ov] aga94 ,illu/ration3 ,,fig4 #bh4--,/rutt+ ( ,timb] ,po/s & ,railway ,rail ,caps4 ,illu/ration3 ,,fig4 #bi4--,/rutt+ made entirely ( ,railway ,rails4 ,iron ,/rutt+ 9 ,head+s4--,9 /rutt+ ! head+s ! cross frames h a cr[n b> consi/+ ( a section ( old railway rail c>ri$ ei!r by wood or iron side po/s4 ,:5 wood5 side po/s are us$ _! upp] ends h a dovetail mortise1 & are b\nd ) an iron b&1 z %[n by ,fig4 #bh4 ,! base ( ! rail cr[n b> is set into ! dovetail mortise & fa/5$ by w$ges4 ,:5 iron side po/s are employ$ !y usually consi/ ( sections ( railway rails1 & ! cr[n b> is atta*$ to !m by fi%-plate connections1 z %[n by ,fig4 #bi4 ,! iron cross frames are set up z ! head+ advances1 & c>ry ! plank lagg+ or pol+-bo>ds1 exactly 9 ! same mann] z ! timb] cross frames previ\sly describ$4 ,illu/ration3 ,,fig4 #cj4--,rziha's ,comb9$ ,/rutt+ & ,c5t]+ ( ,ca/ ,iron4 ,illu/ration3 ,,fig4 #ca4--;,ca/-,iron ,segm5t ( ,rziha's ,/rutt+ & ,c5t]+4 ,full ,section ,iron ,/rutt+4--,! iron /rutt+ devis$ by ,mr4 ,rziha = full section "w is %[n by ,fig4 #cj4 ,briefly describ$1 x consi/s ( v\ssoir-%ap$ ca/-iron segm5ts1 :i* are built up 9 ar* =m4 ,fig4 #ca %[s ! con/ruction ( "o ( ! segm5ts1 all ( :i* are alike1 ) ! exception ( ! cr[n segm5t1 :i* has a mortise & t5on jo9t :i* is kept op5 by fill+ ! mortise ) s&4 ,! segm5ts are bolt$ toge!r by means ( suitable bolt-holes 9 ! v]tical flanges1 & :5 fully connect$ =m an ar* rib ( ca/ iron4 ,?is ar* rib1 ,a1 ,fig4 #cj1 c>ries a s]ies ( angle or ,t-iron frames b5t into approximately v\ssoir %ape1 z %[n at ,b1 ,fig4 #cj4 ,above ^! frames are ins]t$ ! pol+-bo>ds1 runn+ longitud9ally1 & spann+ ! di/ance betwe5 consecutive ar* ribs4 ,by remov+ ! b5t iron frames ! ca/-iron rib =ms a c5t] ^u :i* to con/ruct ! masonry4 ,f9ally1 to remove ! ca/-iron rib itself1 ! s& is drawn out ( ! mortise & t5on jo9t 9 ! cr[n segm5t1 :i* all[s ! jo9t to close1 & loos5 ! segm5ts s t !y are easily unbutt$4 ,! illu/ration1 ,fig4 #cj1 %[s longitud9al pol+-bo>ds2 m (t5 longitud9al cr[n b>s ( railway rails span ! space betwe5 connective ar* ribs1 & support transv]se pol+-bo>ds4 ,9 build+ ! masonry1 "w is begun at ! bottom on ea* side1 ! b5t iron frames be+ remov$ "o aft] ano!r to give room = ! masonry4 ,z ea* frame is remov$1 x is replac$ ) a sort ( screw-jack to support ! pol+-bo>ds until ! masonry is suffici5tly complet$ to all[ _! removal4 ,! int]ior brac+ ( ! ar* rib %[n at a a & b b consi/s ( railway rails c>ri$ by brackets ca/ on to ! segm5ts4 ,a simil> brac+ ( rails connects ! successive ar* ribs4 ,^! l9es ( brac+ s]ve to c>ry ! scaffold+ ^u :i* ! masons "w 9 build+ ! l9+4 ,illu/ration3 ,,fig4 #cb4--;,ca/-,iron ,segm5tal ,/rutt+ = ,%afts4 ,iron ,%aft ,/rutt+4--,9 s(t-gr\nd %aft "w1 ! use ( an iron /rutt+1 consi/+ ( consecutive ca/-iron r+s1 has sometimes be5 employ$ to advantage4 ,fig4 #cb %[s ! con/ruction ( "o ( ^! r+s1 :i*1 x w be se51 is compos$ ( f\r segm5ts connect$ to ea* o!r by means ( bolt$ flanges4 ,! holes %[n 9 ! circumf]5tial web ( ! r+ are to all[ = ! seepage f ! e>? side walls4 ,! me?od ( plac+ ?is cyl9drical /rutt+ is to />t ) a r+ hav+ a cutt+-edge4 ,by means ( excavation inside ! r+1 & by ramm+1 ! r+ is sunk into ! gr\nd a di/ance equal to its height4 ,ano!r r+ is !n fa/5$ by special hooks on top ( ! fir/ "o1 & ! s9k+ cont9u$ until ! second r+ is d[n flu% ) ! surface4 ,a ?ird r+ is !n add$1 & s on until ! entire %aft is excavat$ & /rutt$4 ,z 9 timb] %aft /rutt+1 ! solid iron r+ /rutt+ is c>ri$ d[n only to ! top ( ! tunnel section1 & bel[ ?is po9t !re is an op5 timb] or iron support+ framework4 ,,*apt] ,,vi4 ,,me?ods ,,( ,,haul+ ,,9 ,,tunnels4 ,! transportation f "o po9t to ano!r )9 ! tunnel & its %afts ( any mat]ial1 :e!r x is excavat$ spoil or con/ruction mat]ial1 is def9$ z haul+4 ,9 all eng9e]+ con/ruction1 ! transportation ( excavat$ mat]ials1 & mat]ials = con/ruction1 con/itutes a v important "p ( ! exp5se ( ! "w2 b haul+ 9 tunnels :]e ! room is v limit$1 & :]e "w is con/antly 9 progress ov] & at ! sides ( ! track1 is a p>ticul>ly exp5sive process4 ,haul+ 9 tunnels may be done ei!r by way ( ! entrances1 or by way ( ! %afts1 or by way ( bo? ! entrances & %afts4 ,illu/ration3 ,,fig4 #cc4--,plat=m ,c> = ,tunnel ,"w4 ,haul+ by ,way ( ,entrances4--,:5 ! haul+ is done by ! way ( ! entrances1 ! mat]ials to be haul$ are tak5 directly f ! po9t ( con/ruction to ! entrances1 or 9 ! opposite direction1 by means ( special c>s ( diff]5t patt]ns4 ,= g5]al purposes1 ^! diff]5t patt]ns ( c>s may be gr\p$ into ?ree classes1--plat=m-c>s1 dump-c>s1 & box-c>s4 ,repres5tative examples ( ^! sev]al classes ( c>s are %[n 9 ,figs4 #cc to #cff inclusive1 b x w be readily und]/ood t !re are _m o!r =ms4 #f ,reproduc$ f catalogue ( ,ar?ur ,koppel1 ,new ,york4 ,briefly describ$1 plat=m-c>s 7,fig4 #cc7 consi/ ( a wood5 plat=m m\nt$ on tracks1 & !y are usually employ$ = ! transportation ( timb]1 ties1 etc4 ,dump-c>s are us$ 9 great] numb]s 9 tunnel "w ?an any o!r =m4 ,fig4 #cd %[s a dump-c> ( metal con/ruction1 & ,fig4 #ce "o con/ruct$ ) a metal "u-frame & wood5 box4 ,^! c>s are made to run on n>r[-gauge tracks1 & usually h a capacity ( ab\t "o to "o & "o-half cubic y>ds4 ,box-c>s are m ext5sively employ$ 9 ,europe = tunnel "w ?an 9 ,am]ica4 ,fig4 #cf %[s a typical ,european box-c> = tunnel "w4 ,x is made ei!r to run on n>r[-gauge or /&>d-gauge tracks4 ,illu/ration3 ,,fig4 #cd4--;,iron ,dump-,c> = ,tunnel ,"w4 ,illu/ration3 ,,fig4 #ce4--,wood5 ,dump-,c> = ,tunnel ,"w4 ,illu/ration3 ,,fig4 #cf4--;,box-,c> = ,tunnel ,"w4 ,x is usually desirable 9 tunnel "w to employ c>s ( diff]5t =ms = diff]5t p>ts ( ! "w4 ,9 rock tunnels x is a common practice to use n>r[-gauge c>s ( small size 9 ! head+s1 & l>g]1 broad-gauge c>s = ! enl>gem5t ( ! pr(ile4 ,:]e n>r[-gauge c>s are employ$ = all purposes1 x w also be f\nd m conv5i5t to use plat=m-c>s = h&l+ ! con/ruction mat]ial1 & dump-c>s = remov+ ! spoil4 ,! ext5t to :i* x is desirable to use c>s ( diff]5t =ms w dep5d ^u ! "* & conditions ( ! "w1 & p>ticul>ly ^u h[ f> x is possible to in/all ! p]man5t track4 ,z a g5]al ride1 x is consid]$ pref]able to lay ! p]man5t tracks at once1 & d all ! haul+ ^u !m1 s t z soon z ! tunnel is complet$1 tra9s may pass ?r\gh )\t delay4 ,to :at ext5t ?is may be done1 or :e!r x c be done at all or n1 dep5ds ^u ! me?od ( excavation & o!r local conditions4 ,9 s(t-gr\nd tunnels excavat$ by ! ,engli% or ,au/rian me?ods1 x is q possible to lay ! p]man5t tracks at fir/1 s9ce ! :ole section is excavat$ at once1 & ! excavation is kept b a little ahead ( ! complet$ tunnel4 ,9 rock tunnels1 :]e ! head+ is driv5 f> ahead ( ! complet$ section1 x is1 ( c\rse1 impossible to keep ! p]man5t track close to ! advance "w1 & n>r[-gauge tracks mu/ be laid 9 ! head+4 ,! same ?+ is true 9 s(t-gr\nd tunnels driv5 by successive head+s & drifts4 ,9 ^! cases1 !re=e1 :]e n>r[-gauge tracks h to be us$ = "s portions ( ! "w anyway1 ! "q comes up :e!r x is pref]able to use tempor>y n>r[-gauge tracks ?r\gh\t1 or to lay ! p]man5t track z f> ahead z possible1 & !n ext5d n>r[-gauge tracks to ! advance excavation4 ,9 ! latt] case x w1 ( c\rse1 be necess>y to trans-%ip ea* load f ! n>r[-gauge to ! /&>d-gauge c>s1 or vice v]sa1 :i* means extra co/ & tr\ble4 ,to avoid ?is1 ! me?od is sometimes adopt$ ( lay+ a ?ird rail betwe5 ! /&>d-gauge rails1 s t ei!r /&>d- or n>r[-gauge c>s may be transport$ ov] ! l9e4 ,:atev] =m ! local conditions may require ! sy/em ( con/ruction tracks to assume1 x may be set d[n z a g5]al rule t ! p]man5t tracks %\ld be kept z f> advanc$ z possible1 & tempor>y tracks employ$ only :]e ! p]man5t tracks are impracticable4 ,! motive p[] employ$ = haul+ 9 tunnels may be furni%$ by animals or by me*anical motors4 ,animal p[] is g5]ally employ$ 9 %ort tunnels & 9 ! advance head+s & gall]ies4 ,9 long tunnels1 or :]e ! excavat$ mat]ial has to be transport$ "s di/ance away f ! tunnel1 me*anical p[] is pref]able1 = obvi\s reasons4 ,! motors mo/ us$ are small /eam locomotives1 special compress$-air locomotives1 & electric motors4 ,compress$ air & electric locomotives are built 9 v>i\s =ms1 & are p>ticul>ly well adapt$ = tunnel "w because ( _! small dim5sions1 & fre$om f smoke & heat4 ,haul+ by ,way ( ,%afts4--,:5 ! excavat$ mat]ial & mat]ials ( con/ruction are h&l$ ?r\gh %afts1 ! op]ation ( haul+ may be divid$ into ?ree processes3 ! transportation ( ! mat]ials along ! floor ( ! tunnel1 ! hoi/+ ( !m ?r\gh ! %aft1 & ! surface transportation f & to ! m\? ( ! %aft4 ,^! ?ree op]ations %\ld be arrang$ to "w 9 h>mony ) ea* o!r1 s z to avoid wa/e ( "t & unnecess>y h&l+ ( ! mat]ials4 ,an endeavor %\ld be made to avoid1 if possible1 break+ or trans-%ipp+ ! load f ! "t x />ts at ! head+ until x is dump$ at ! spoil bank4 ,?is c be accompli%$ 9 two ways4 ,"o way is to hoi/ ! boxes ( ! c>s f _! trucks at ! bottom ( ! %aft1 & place !m on simil> trucks runn+ on ! surface tracks4 ,! o!r way is to run ! load$ c>s on to ! elevator plat=m at ! bottom1 hoi/ !m1 & !n run !m on to ! surface tracks4 ,if ! fir/ me?od is employ$1 ! c> box is usually made ( metal1 & is provid$ at its top edges ) hooks or e>s to :i* to atta* ! hoi/+ cables4 ,:5 ! second me?od is us$1 ! elevator plat=m has tracks laid on x :i* connect ) ! tracks on ! tunnel floor1 & also ) ^? on ! surface4 ,hoi/+ ,ma*9]y4--,! ma*9es mo/ commonly employ$ = hoi/+ purposes 9 tunnel %afts are /eam hoi/+ eng9es1 horse g9s1 & w9dlasses op]at$ by h&4 ,w9dlasses & horse g9s are r crude ma*9es = hoi/+ loads1 & are us$ only 9 special circum/ances1 :]e ! %aft is ( small dep?1 :5 ! am\nt ( mat]ial to be hoi/$ is small1 or :]e = any reason ! use ( hoi/+ eng9es is preclud$4 ,! /eam hoi/+ eng9e is ! /&>d ma*9e = ! rapid lift+ ( heavy v]tical loads4 ,rec5tly oil eng9es & electric hoi/s h also come to be us$ to "s ext5t1 & "u c]ta9 conditions ^! ma*9es possess notable advantages4 ,! con/ruction ( h& w9dlasses is famili> to e "o4 ,9 tunnel "w ?is device is locat$ directly ov] ! %aft1 ) its axis a little m ?an half a man's height1 s t ! crank h&le does n rise above ! %\ld] l9e4 ,to develop its greate/ effici5cy ! hoi/+ rope is pass$ ar\nd ! w9dlass drum s t ! two ends hang d[n ! %aft1 & z "o end desc5ds ! o!r asc5ds4 ,a skip1 or bucket1 is atta*$ to ea* ( ! rope ends2 & by load+ ! desc5d+ skip ) con/ruction mat]ials & ! asc5d+ skip ) spoil1 ! two skip loads t5d to balance ea* o!r1 ?us increas+ ! capacity ( ! w9dlass1 & decreas+ ! manual labor requir$ to op]ate x4 ,skips v>y+ f #j4c cu4 yd4 to #j4e cu4 yd4 are us$4 ,! horse g9 consi/s ( a v]tical cyl9d] or drum provid$ ) radial arms to :i* ! horses are hit*$1 :i* revolve ! cyl9d] by walk+ ar\nd x 9 a circle4 ,! hoi/+ rope is rove ar\nd ! drum s t ! two ends ext5d d[n ! %aft ) skips atta*$1 z describ$ 9 speak+ ( ! h& w9dlass4 ,! p[] ( ! horse g9 is1 ( c\rse1 mu* great] ?an t ( a w9dlass op]at$ by h&1 skips ( #a cu4 yd4 capacity be+ commonly us$4 ,horse g9s are no long] economical hoi/+ ma*9es1 accord+ to "o prom95t au?ority1 :5 ,v7,h #bj7 #ejjj1 :]e ,v equals ! volume ( mat]ial to be hoi/$1 & ,h equals ! height ( ! hoi/1 ! weight ( ! excavat$ mat]ial be+ #bajj lbs4 p] cu4 yd4 ,z a g5]al rule1 h[ev]1 x is assum$ t x is n economical to employ horse g9s ) a dep? ( %aft exce$+ #aej ft4 ,z already /at$1 ! mo/ effici5t & mo/ commonly us$ device = hoi/+ at tunnel %afts is ! /eam hoi/+ eng9e4 ,!re are num]\s build]s ( hoi/+ eng9es1 ea* ( :i* manufactures sev]al patt]ns & sizes ( eng9es4 ,9 ea* case1 h[ev]1 ! app>atus consi/s ( a boil] supply+ /eam to a horizontal eng9e :i* op]ates "o or m rope drums4 ,! eng9es are always rev]sible4 ,!y may be employ$ to hoi/ ! skips directly1 or to op]ate elevators ^u :i* ! skips or c>s are load$4 ,9 ei!r case ! hoi/+ ropes pass f ! eng9e drum to & ar\nd v]tical %eaves situat$ directly ov] ! %aft s z to secure ! necess>y v]tical travel ( ! ropes d[n ! %aft4 ,:]e ! %aft is divid$ into two comp>tm5ts1 ea* hav+ an elevator or hoi/1 d\ble-drum eng9es are employ$1 "o drum be+ us$ = ! op]ations 9 "o comp>tm5t1 & ! o!r = ! op]ations 9 ! o!r comp>tm5t4 ,:]e ! "w is to be ( consid]able duration1 or :5 x is done 9 cold wea!r1 m or less elaborate %elt]s or eng9e h\ses are built to cov] & protect ! ma*9]y4 ,*oice betwe5 ! me?od ( hoi/+ ! skips directly1 & ! me?od ( us+ elevators1 dep5ds ^u ! ext5t & "* ( ! "w4 ,:]e l>ge quantities ( mat]ial are to be hoi/$ rapidly1 x is g5]ally consid]$ pref]able to employ elevators in/ead ( hoi/+ ! skips directly4 ,9 direct hoi/+ at high spe$1 oscillations are likely to be produc$ :i* may da% ! skips aga9/ ! sides ( ! %aft & cause accid5ts4 ,! loads :i* c be c>ri$ 9 s+le skips are also small] ?an ^? possible :]e elevators are us$2 & ?is1 comb9$ ) ! sl[] hoi/+ spe$ requir$1 r$uces ! capacity ( ?is me?od1 z comp>$ ) ! use ( elevators4 ,:]e elevators are employ$1 h[ev]1 ! plant requir$ is mu* m ext5sive & co/ly2 x compris+ n only ! elevator c>s ) _! safety devices1 etc41 b ! con/ruction ( a guid+ framework = ^! c>s 9 ! tunnel %aft4 ,= ^! v>i\s reasons ! elevator becomes ! pref]able hoi/+ device :]e ! quantity ( mat]ial to be h&l$ is l>ge1 :]e ! %afts are deep1 & :]e ! "w w ext5d ov] a long p]iod ( "t2 b :5 ! contr>y conditions are ! case1 direct hoi/+ ( ! skips is g5]ally ! *eap]4 ,! eng9e] has to integrate ! v>i\s factors 9 ea* individual case1 & det]m9e :i* me?od w be/ fulfill 8 purpose1 :i* is to h&le ! mat]ial at ! lea/ co/ )9 ! giv5 "t & conditions4 ,illu/ration3 ,,fig4 #cg4--;,elevator ,c> = ,tunnel ,%afts4 ,! con/ruction ( elevators = tunnel "w is simple4 ,! elevator c> consi/s usually ( an op5 framework box ( timb] & iron1 hav+ a plank floor on :i* c> tracks are laid1 & its ro( arrang$ = connect+ ! hoi/+ cable 7,fig4 #cgg74 ,rigid con/ruction is necess>y to resi/ ! hoi/+ /ra9s4 ,! sides ( ! c> are usually design$ to slide aga9/ timb] guides on ! %aft walls4 ,"s =m ( safety device1 ( :i* !re are sev]al k9ds1 %\ld be employ$ to prev5t ! fall ( ! elevator1 9 case ! hoi/+ rope breaks1 or "s mi%ap occurs to ! hoi/+ ma*9]y1 :i* endang]s ! fall ( ! c>4 ,speak+ tubes & electric-bell signals %\ld also be provid$ to secure communication betwe5 ! top & bottom ( ! %aft4 #g ,reproduc$ f ! catalogue ( ! ,l$g]wood ,manufactur+ ,company1 ,new ,york4 ,,*apt] ,,vii4 ,,types ,,( ,,c5t]s ,,& ,,molds ,,employ$ ,,9 ,,con/ruct+ ,,tunnel ,,l9+s ,,( ,,masonry4 ,! masonry l9+ ( a tunnel may be describ$ z consi/+ ( two or m segm5ts ( circul> ar*es comb9$ s z to =m a cont9u\s solid r+ ( masonry4 ,to direct ! op]ations ( ! masons 9 con/ruct+ ?is masonry r+1 templates or patt]ns are provid$ :i* %[ ! exact dim5sions & =m ( ! sectional pr(ile :i* x is desir$ to secure4 ,^! patt]ns or templates w v>y 9 numb] & con/ruction ) ! =m ( l9+ & ! me?od ( excavation adopt$4 ,:]e ! excavation is fully l9$ on all f\r sides1 ! masonry "w is usually divid$ into ?ree p>ts1--! inv]t or floor masonry1 ! side-wall masonry1 & ! ro(-ar* masonry4 ,at lea/ "o sep>ate patt]n has to be employ$ 9 con/ruct+ ea* ( ^! p>ts ( ! l9+2 & !y are kn[n respectively z gr\nd molds1 lead+ frames1 & ar* c5t]s1 or simply c5t]s4 ,9 ! foll[+ p>agraphs ! =m & con/ruction usually employ$ = ea* ( ^! ?ree k9ds ( patt]ns is describ$4 ,gr\nd ,molds4--,gr\nd molds are employ$ 9 build+ ! tunnel inv]t4 ,!y are g5]ally con/ruct$ ( #c-;in* plank cut exactly to ! =m & dim5sions ( ! inv]t masonry z %[n 9 ,fig4 #ch4 ,to p]mit ( conv5i5ce ( h&l+ 9 a re/rict$ space1 !y are g5]ally made 9 two p>ts1 :i* are jo9$ at ! middle by means ( iron fi%-plates & bolts4 ,ei!r "o or two gr\nd molds may be employ$4 ,:]e two molds are us$ !y are set up a %ort di/ance ap>t1 & cords are /ret*$ f "o to ! o!r p>allel to ! axis ( ! tunnel1 by :i* ! masons are guid$ 9 _! "w4 ,extreme c>e has to be tak5 9 sett+ ! molds to ensure t !y are fix$ at ! prop] grade1 & are 9 a plane normal to ! axis ( ! tunnel4 ,:]e only "o gr\nd mold is employ$1 ! f9i%$ masonry is dep5d$ ^u to supply ! place ( ! second mold1 cords be+ /ret*$ f x to ! s+le mold plac$ ! requisite di/ance ahead4 ,! level+ & c5t]+ ( ! molds is accompli%$ by means ( transit & level4 ,illu/ration3 ,,fig4 #ch4--;,gr\nd ,mold = ,con/ruct+ ,tunnel ,inv]t ,masonry4 ,illu/ration3 ,,fig4 #ci4--;,comb9$ ,gr\nd ,mold & ,lead+ ,frame = ,inv]t & ,side ,wall ,masonry4 ,two modifications ( ! =m ( gr\nd mold %[n by ,fig4 #ci are employ$4 ,! fir/ modification is peculi> to ! ,engli% me?od ( excavation1 & consi/s 9 comb9+ ! gr\nd mold ) ! lead+ frame = ! l[] "p ( ! side walls1 z %[n by ,fig4 #ci4 ,! second modification is employ$ :]e ! two halves or sides ( ! inv]t are built sep>ately1 & x consi/s simply 9 us+ "o-half ( ! mold %[n by ,fig4 #ch4 ,:5 ! la/ me?od ( con/ruct+ ! inv]t masonry is resort$ to1 extreme c>e has to be obs]v$ 9 sett+ ! half-mold 9 ord] to avoid error4 ,illu/ration3 ,,fig4 #dj4--,lead+ ,frame = ,con/ruct+ ,side ,wall ,masonry4 ,lead+ ,frames4--,z already /at$1 lead+ frames are ! patt]ns1 or molds1 us$ 9 build+ ! side walls ( ! l9+4 ,l ! gr\nd mold !y are usually built ( plank2 "o side be+ cut to ! curve ( ! pr(ile1 & ! o!r be+ made p>allel to ! v]tical axis ( ! tunnel section4 ,! v]tical side usually has "s arrangem5t by :i* a plumb bob c be atta*$1 z %[n by ,fig4 #dj1 to guide ! workm5 9 erect+ ! frame4 ,! comb9$ lead+ frame & gr\nd mold %[n 9 ,fig4 #ci has already be5 describ$4 ,! use ( ?is frame is possible only :]e ! masonry is begun at ! inv]t & c>ri$ up on ea* side at ! same "t4 ,?is mode ( con/ruction is peculi> to ! ,engli% me?od ( tunnel+2 9 all o!r me?ods ! =m ( sep>ate gr\nd frame %[n by ,fig4 #dj is employ$4 ,! gr\nd frames are l9$ 9 & level$ up by transit & level2 &1 z 9 sett+ ! gr\nd frames1 c>e mu/ be tak5 to secure accuracy 9 bo? direction & elevation4 ,ar* ,c5t]s4--,! template or =m ^u :i* ! ro( ar* is built is call$ a c5t]4 ,unlike ! gr\nd molds & lead+ frames1 ! ar* c5t]s h to support ! weight ( ! masonry & ! ro( pressures dur+ ! con/ruction ( ! l9+1 & !y1 !re=e1 require to be made /rong4 ,ow+ to ! fact t ! pressures are indet]m9ate1 x is impossible to design a rational c5t]1 & resort is _h to ^? con/ructions :i* pa/ exp]i5ce has %[n to "w satisfactorily "u simil> conditions4 ,9 a g5]al way x c always be assum$ t ! con/ruction %\ld be z simple z possible1 t ! c5t] %\ld be s design$ t x c be set up & remov$ ) ! lea/ possible labor1 & t ! diff]5t pieces ( ! framework & lagg+ %\ld be z %ort z possible1 = conv5i5ce 9 h&l+4 ,tunnel c5t]s are usually compos$ ( two p>ts1--a mold or curv$ surface ^u :i* ! masonry re/s1 & a framework :i* supports ! mold4 ,! curv$ surface or mold consi/s ( a lagg+ ( n>r[ bo>ds runn+ p>allel to ! tunnel axis1 :i* re/s ^u ! ar*$ top memb]s ( two or m consecutive support+ frames4 ,! support+ frame is built 9 ! =m ( a truss1 & mu/ be made /rong en\gh to )/& ! heavy sup]impos$ loads1 consi/+ ( ! ar* masonry dur+ con/ruction1 & ( ! ro( pressures :i* are transf]r$ to ! c5t] :5 ! /rutt+ is remov$ to all[ ! masonry to be plac$4 ,! framework ( ! c5t] is support$ ei!r by po/s re/+ ^u ! floor ( ! excavation1 or ^u ! inv]t masonry :5 ?is is built fir/1 z 9 ! ,engli% & ,au/rian me?ods1 or x may be support$ directly ^u ! gr\nd :]e ! ar* masonry is built fir/1 z 9 ! ,belgian me?od ( tunnel+4 ,9 describ+ ! v>i\s me?ods ( tunnel+ 9 succe$+ *apt]s1 ! c5t] con/ruction & me?od ( support+ ! c5t] peculi> to ea* w be fully expla9$1 & only a few g5]al rem>ks are necess>y "h4 ,c5t]s may be classifi$ accord+ to _! con/ruction & composition into plank c5t]s1 truss c5t]s1 & iron c5t]s4 ,illu/ration3 ,,fig4 #da4--,plank ,c5t] = ,con/ruct+ ! ,ro( ,ar*4 ,"o ( ! mo/ common =ms ( plank c5t]s is %[n by ,fig4 #da4 ,x consi/s ( two half-polygons ^: sides consi/ ( #ae 94 #d ft4 planks hav+ radial end-jo9ts4 ,^! two half-polygons are laid "o ^u ! o!r s t !y break jo9ts1 z %[n by ! figure1 & ! extrados ( ! frame is cut to ! true curve ( ! ro( ar*4 ,! planks commonly us$ = mak+ ^! c5t]s are #d ins4 ?ick1 mak+ ! total ?ickness ( ! c5t] #h ins4 ,plank c5t]s ( ! con/ruction describ$ are suitable only = "w :]e ! pressures to be resi/$ are small1 z 9 tunnels ?r\gh a fairly firm rock1 al?\gh !re h be5 in/ances ( _! successful use 9 s(t-gr\nd tunnels4 ,:]e heavy loads h to be c>ri$1 truss$ c5t]s are g5]ally employ$1 ! trusses be+ compos$ ( heavy squ>e beams ) sc>f$ & t5on$ jo9ts1 re9=c$ by iron plates4 ,diff]5t =ms ( trusses are employ$ 9 ea* ( ! diff]5t me?ods ( tunnel+1 & ea* ( ^! is describ$ 9 succe$+ *apt]s2 b !y are g5]ally ei!r ( ! k+-po/ or que5-po/ type1 or "s modification ( !m4 ,! k+-po/ truss may be us$ alone1 ) or )\t ! tie-beam1 z %[n by ,fig4 #db2 b g5]ally a que5-po/ truss is made to =m ! base ( support = a small] k+-po/ truss m\nt$ on its top4 ,?is arrangem5t gives a trapezoidal =m to ! c5t]1 :i* approa*es closely to ! ar* pr(ile4 ,ow+ to ! "* ( ! pressures transmitt$ to ! c5t]1 ! usual t5sion memb]s c be made v light4 ,illu/ration3 ,,fig4 #db4--,truss$ ,c5t] = ,con/ruct+ ! ,ro( ,ar*4 ,! comb9$ c5t] & /rutt+ sy/em devis$ by ,mr4 ,rziha has already be5 describ$ 9 a previ\s *apt]4 ,9 rec5t ,european tunnel "w q ext5sive use has also be5 made ( iron c5t]s consi/+ ( sev]al segm5ts ( curv$ ,i-beams1 connect$ by fi%-plate jo9ts s z to =m a semi-circul> ar* rib4 ,! ends or feet ( ^! ,i-beam ribs h be>+-plates or %oes made by rivet+ angles to ! ,i-beams4 ,c5t]s con/ruct$ 9 a simil> mann]1 b made ( sections ( old railway rail1 7 us$ 9 c>ry+ out ! tunnel "w on ! ,rh9e ,riv] ,railroad 9 ,g]many4 ,! advantages claim$ = iron c5t]s are t !y take up less room1 & t !y c be us$ ov] & ov] aga94 ,sett+ ,up ,c5t]s4--,accord+ to ! me?od ( excavation foll[$ 9 build+ ! tunnel1 ! c5t]s = build+ ! ro( ar* may h to be support$ by po/s re/+ on ! tunnel floor2 or :]e ! ar* is built fir/1 z 9 ! ,belgian & ,italian me?ods1 !y may be c>ri$ on block+ re/+ on ! unexcavat$ e>? bel[4 ,:i*ev] me?od is employ$1 an unyield+ support is ess5tial1 & c>e mu/ be tak5 t ! c5t]s are erect$ & ma9ta9$ 9 a plane normal to ! tunnel axis4 ,to prev5t deflection & twi/+1 ! consecutive c5t]s are usually brac$ toge!r by longitud9al /ruts or by braces runn+ to ! adjac5t /rutt+4 ,only skill$ & exp]i5c$ workm5 %\ld be employ$ 9 erect+ ! c5t]s2 & !y %\ld "w "u ! imm$iate direction ( ! eng9e]1 :o mu/ e/abli% ! axis & level ( ea* c5t] by transit & level4 ,lagg+4--,by ! lagg+ is meant ! cov]+ ( n>r[ longitud9al bo>ds re/+ ^u ! upp] curv$ *ords ( ! c5t]s1 & spann+ ! op5+ betwe5 consecutive c5t]s4 ,?is lagg+ =ms ! curv$ surface or mold ^u :i* ! ar* masonry is laid4 ,:5 ! ro( ar* is ( a%l> masonry ! /rips ( lagg+ are seldom plac$ ne>] toge!r ?an ! jo9ts ( ! consecutive r+ /ones1 b 9 brick ar*es !y are laid close toge!r4 ,besides ! weight ( ! ar* masonry1 ! lagg+ timb]s support ! %ort props :i* keep ! pol+-bo>ds 9 place aft] ! /rutt+ is remov$ & until ! ar* masonry is complet$4 ,/rik+ ! ,c5t]s4--,! c5t]s are usually br\ght to ! prop] elevation by means ( wood5 w$ges ins]t$ betwe5 ! sill ( ! c5t] & its support1 or betwe5 ! bottom ( ! po/s c>ry+ ! c5t] & ! tunnel floor4 ,^! w$ges are usually made ( h>d wood1 & are ab\t #f ins4 wide by #d ins4 ?ick by #ah ins4 long4 ,to /rike ! c5t] aft] ! ar* masonry is complet$1 ^! w$ges are )drawn1 ?us all[+ ! c5t] to fall cle> ( ! masonry4 ,usually ! c5t] is n remov$ imm$iately aft] /rik+1 s t if ! ar* masonry fails ! ru9s w rema9 ^u ! c5t]4 ,! me?od ( /rik+ ! iron c5t] devis$ by ,mr4 ,rziha has be5 describ$ 9 ! previ\s *apt] on /rutt+4 ,,*apt] ,,viii4 ,,me?ods ,,( ,,l9+ ,,tunnels4 ,tunnels 9 s(t soils & 9 loose rock1 & rock liable to dis9tegration1 are always provid$ ) a l9+ to hold ! walls & ro( 9 place4 ,?is l9+ may cov] ! entire sectional pr(ile ( ! tunnel1 or only a "p ( x1 & x may be con/ruct$ ( timb]1 iron1 iron & masonry1 or1 m commonly1 ( masonry alone4 ,timb] ,l9+4--,timb] is seldom employ$ 9 l9+ tunnels except z a tempor>y exp$i5t1 & is replac$ by masonry z soon z circum/ances w p]mit4 ,9 ! fir/ con/ruction ( _m ,am]ican railways1 ! necessity = extreme economy 9 con/ruction1 & ( gett+ ! l9e op5 = traffic z soon z possible1 caus$ ! eng9e]s to l9e _m tunnels ) timb]1 :i* 0 pl5tiful & *eap4 ,except = _! small co/ & ! ease & rapidity ) :i* !y c be con/ruct$1 h[ev]1 ^! timb] l9+s possess few advantages4 ,x is only ! matt] ( a few ye>s :5 ! decay ( ! timb] makes x necess>y to rebuild !m1 & !re is always ! s]i\s dang] ( fire4 ,9 sev]al in/ances timb]-l9$ tunnels 9 ,am]ica h be5 burn$ out1 caus+ s]i\s delays 9 traffic1 & necessitat+ complete recon/ruction4 ,usually ?is recon/ruction has consi/$ 9 sub/itut+ masonry 9 place ( ! orig9al timb] l9+4 ,9 a succe$+ *apt] a description w be giv5 ( "s ( ! me?ods employ$ 9 replac+ timb] tunnel l9+s ) masonry4 ,v>i\s =ms ( timb] l9+ are employ$1 ( :i* ,fig4 #dd & ! illu/rations 9 ! *apt] discuss+ ! me?ods ( rel9+ timb]-l9$ tunnels ) masonry are typical examples4 ,illu/ration3 ,cross ,section4 ,longitud9al ,section4 ,,figs4 #dc & #dd4--;,a ,typical ,=m ( ,timb] ,l9+ = ,tunnels4 ,iron ,l9+4--,! use ( iron l9+ = tunnels 0 introduc$ fir/ on a l>ge scale by ,mr4 ,pet] ,william ,b>l[ 9 #ahfi1 = ! second tunnel "u ! ,riv] ,?ames at ,london1 ,engl&1 & x has greatly ext5d$ s9ce t "t4 ,! l9+ ( ! second ,?ames tunnel consi/$ ( cyl9drical ca/-iron r+s #h ft4 9 diamet]1 ! abutt+ edges ( ! successive r+s be+ flang$ & provid$ ) holes = bolt fa/5+s4 ,ea* r+ 0 made up ( f\r segm5ts1 ?ree ( :i* 7 long] ?an quadrants1 & "o mu* small] =m+ ! 8key-/one0 or clos+ piece4 ,^! segm5ts 7 connect$ to ea* o!r by flanges & bolts4 ,to make ! jo9ts tight1 /rips ( p9e or cem5t & hemp y>n 7 ins]t$ betwe5 ! flanges4 ,s9ce ! con/ruction ( ! second ,?ames tunnel1 iron l9+ has be5 employ$ = a great _m subm>9e tunnels 9 ,engl&1 ,cont95tal ,europe1 & ,am]ica1 "s ( !m hav+ a section ov] #bh ft4 9 diamet]4 ,:]e circul> iron l9+ is employ$1 ! bottom "p ( ! section is level$ up ) concrete or brick masonry to c>ry ! tracks1 & ! :ole int]ior ( ! r+ is cov]$ ) a cem5t pla/] l9+ deep en\gh ?or\ghly to emb$ ! int]ior jo9t flanges4 ,9 ! succe$+ *apt] describ+ ! me?ods ( driv+ tunnels by %ields sev]al =ms ( iron tunnel l9+ are fully describ$4 ,iron & ,masonry ,l9+4--,dur+ rec5t ye>s a =m ( comb9$ masonry & iron l9+ has be5 ext5sively employ$ 9 con/ruct+ city und]gr\nd railways 9 bo? ,europe & ,am]ica4 ,g5]ally ?is =m ( l9+ is built ) a rectangul> section4 ,two types ( con/ruction are employ$4 ,9 ! fir/1 masonry side walls c>ry a flat ro( ( gird]s & beams1 :i* c>ry a tr\gh floor+ fill$ ) concrete1 or betwe5 :i* are sprung concrete or brick ar*es4 ,sometimes ! ro( fram+ consi/s ( a s]ies ( p>allel ,i-beams laid transv]sely across ! tunnel1 & 9 o!r cases transv]se plate gird]s c>ry longitud9al ,i-beams4 ,9 ! second type ( con/ruction ! ro( gird]s are support$ by columns emb$d$ 9 ! side walls4 ,:]e ! tunnel provides = two or f\r tracks1 int]m$iate column supports are 9 "s cases introduc$ betwe5 ! side columns4 ,9 ?is con/ruction ! ro(+ consi/s ( concrete fill$ tr\ghs or ( concrete or brick ar*es1 z 9 ! con/ruction fir/ describ$4 ,examples ( comb9$ masonry & iron tunnel l9+ are illu/rat$ 9 ! succe$+ *apt] on tunnel+ "u city /reets4 ,masonry ,l9+4--,! =m ( tunnel l9+ mo/ commonly employ$ is brick or /one masonry4 ,concrete & re9=c$ concrete masonry l9+ has be5 employ$ 9 sev]al tunnels built 9 rec5t ye>s4 ,! masonry l9+ may inclose ! :ole section or only a "p ( x4 ,! floor or inv]t is ! "p mo/ commonly omitt$2 b sometimes also ! side walls & inv]t are bo? omitt$1 & ! l9+ is conf9$ simply to an ar* support+ ! ro(4 ,! ro( ar*1 ! side walls1 & ! inv]t compose ! tunnel l9+2 & all ?ree may consi/ ( /one or brick alone1 or /one side walls may be employ$ ) brick inv]t & ro( ar*4 ,rubble-/one masonry is usually employ$1 except at ! entrances1 :]e ! masonry is expos$ to view4 ,"h a%l> masonry is usually us$4 ,! /one select$ = tunnel l9+ %\ld be ( a durable quality :i* wea!rs well4 ,:]e bricks are us$ !y %\ld be ( good quality4 ,ow+ to ! comp>ative ease ) :i* brick ar*es c be built1 !y are g5]ally us$ to =m ! ro( ar*1 ev5 :]e ! side walls are ( /one masonry4 ,masonry l9+ may be built 9 ! =m ( a s]ies ( sep>ate r+s1 or 9 ! =m ( a cont9u\s /ructure ext5d+ f "o end ( ! tunnel to ! o!r4 ,! latt] me?od ( con/ruction produces a /rong] /ructure2 b 9 case ( failure by cru%+1 ! damage done is likely to be m widespread ?an :]e sep>ate r+s are employ$1 "o or two ( :i* may fail )\t injury to ! o!rs adjac5t to !m4 ,! con/ruction is also some:at simpl] :]e sep>ate r+s are employ$1 s9ce no provision has to be made = bond+ ! :ole l9+ into a cont9u\s /ructure4 ,:]e a s]ies ( sep>ate r+s is employ$1 ! l5g? ( ea* r+ runs f #e ft4 up to #bj ft41 x dep5d+ ^u ! "* ( ! mat]ial p5etrat$1 & ! me?od ( con/ruction employ$4 ,= ! purpose ( detail$ discussion ! con/ruction ( masonry l9+ may be divid$ into f\r p>ts1--! side-wall f\ndations1 ! side walls !mselves1 ! ro( ar*1 & ! inv]t4 ,concrete & re9=c$ concrete l9+s are n[ ext5sively us$ on acc\nt ( *eapness & facility ( h&l+1 b !y h ! great disadvantage ( resi/+ pressure aft] !y become h>d1 :i* is "s "t aft] be+ plac$4 ,! /rutt+ %\ld1 !re=e1 be left to support ! ro( s z to prev5t direct pressure on ! fre% mat]ial4 ,! ro(1 z a rule1 is support$ by longitud9al planks held 9 position by five or sev5 segm5ts ( ar*$ frames plac$ across ! tunnel4 ,a l>ge quantity ( timb] & c>p5t] "w is ?us entirely wa/$ & ^! co/ly items1 9 _m cases1 make ! concrete l9+ ( a tunnel m exp5sive ?an ! "o built ( brick & /one4 ,to avoid ^! inconv5i5ces tunnels h be5 successfully l9$ ) concrete on ! side walls & concrete blocks 9 ! ar*es4 ,^! blocks h be5 built by h& & mold$ 9 ! %ape ( ! ar* v\ssoirs4 ,f\ndations4--,9 tunnels ?r\gh rock ( a h>d & durable "* ! f\ndations = ! side walls are usually laid directly on ! rock4 ,9 loose rock1 or rock liable to dis9tegration1 ?is me?od ( con/ruction is n g5]ally a safe "o1 & ! f\ndation excavation %\ld be sunk to a dep? at :i* ! atmosph]ic influ5ces _c affect ! f\ndation b$4 ,9 ei!r case ! f\ndation masonry is made ?ick] ?an t ( ! side walls prop]1 s z to di/ribute ! pressure ov] a great] area1 & to af=d m room = adju/+ ! side-wall masonry to ! prop] pr(ile4 ,9 yield+ soils a special f\ndation b$ has to be prep>$ = ! f\ndation masonry4 ,9 "s in/ances x is f\nd suffici5t to lay a c\rse ( planks ^u :i* ! masonry is con/ruct$1 b a m solid con/ruction is usually pref]r$4 ,?is is obta9$ by plac+ a concrete foot+ f #a ft4 to #b ft4 deep all along ! bottom ( ! f\ndation tr5*1 or 9 "s cases by s9k+ wells at int]vals along ! tr5* & fill+ !m ) concrete1 s z to =m a s]ies ( support+ pill>s4 ,illu/ration3 ,,fig4 #de4--;,diagram ,%[+ ,=ms ,adopt$ = ,side-,wall ,f\ndations4 ,! =m giv5 to ! f\ndation c\rses & l[] portions ( ! side walls v>ies4 ,:]e a l>ge be>+ area is requir$1 ! back ( ! wall is c>ri$ up v]tically z %[n by ! l9e ,,ab1 ,fig4 #de1 o!rwise ! re> face ( ! wall foll[s ! l9e ( excavation ,,ac4 ,= simil> reasons ! front face ( ! wall may be made v]tical1 z at ,,fg1 or incl9$1 z at ,,fh4 ,! l9e ,,fe indicates ! %elf con/ruction design$ to support ! feet ( ! po/s us$ to c>ry ! ar* c5t]s dur+ ! con/ruction ( ! ro( ar*4 ,side ,walls4--,! con/ruction ( ! side walls above ! f\ndation c\rses is c>ri$ out z any simil> piece ( masonry else:]e w\ld be built4 ,to direct ! "w & insure t ! inn] faces ( ! walls foll[ accurately ! curve ( ! *os5 pr(ile1 lead+ frames previ\sly describ$ are employ$4 ,ro( ,ar*4--,= ! con/ruction ( ! ro( ar*1 ! c5t]s previ\sly describ$ are employ$4 ,beg9n+ at ! edges ( ! c5t] on ea* side1 ! masonry is c>ri$ up a c\rse at a "t1 c>e be+ tak5 to h x progress at ! same rate on bo? sides1 s t ! load br\ght onto ! c5t]+ is symmetrical4 ,z soon z ! c5t]s are erect$1 ! ro( /rutt+ is remov$1 & replac$ by %ort props :i* re/ on ! lagg+ ( ! c5t]s & support ! pol+-bo>ds4 ,^! props are remov$ 9 succession z ! ar* masonry rises along ! curve ( ! c5t]1 & ! space betwe5 ! top ( ! ar* masonry & ! ceil+ ( ! excavation is fill$ ) small /ones pack$ closely4 ,! key/one section ( ! ar* is built la/1 by ins]t+ ! /ones or bricks f ! front edge ( ! ar* r+1 !re be+ no room to set !m 9 f ! top1 z is ! practice 9 ord9>y op5-ar* con/ruction4 ,! key+ ( ! ar* is an especially difficult op]ation1 & only exp]i5c$ m5 skill$ 9 ! "w %\ld be employ$ to p]=m x4 ,! task becomes "o ( unusual difficulty :5 x becomes necess>y to jo9 ! ar*es com+ f opposite directions4 ,inv]t4--,9 all b "o or two me?ods ( tunnel+1 ! inv]t is ! la/ portion ( ! l9+ to be built4 ,9 ! ,engli% me?od ( tunnel+1 ! inv]t is ! fir/ portion ( ! l9+ to be built1 & ! same practice is sometimes necess>y 9 s(t soils :]e !re is dang] ( ! bottoms ( ! side walls be+ squeez$ toge!r by ! lat]al pressures unless ! inv]t masonry is 9 place to hold !m ap>t4 ,! gr\nd molds previ\sly describ$ are employ$ to direct ! con/ruction ( ! inv]t masonry4 ,g5]al ,obs]vations4--,9 describ+ ! con/ruction ( ! ro( ar*1 m5tion 0 made ( ! /one fill+ employ$ betwe5 ! back ( ! masonry r+ & ! ceil+ ( ! excavation4 ,! spaces beh9d ! side walls are fill$ 9 a simil> mann]4 ,! object ( ?is /one fill+1 :i* %\ld be closely pack$1 is to di/ribute ! v]tical & lat]al pressures 9 ! walls ( ! excavation uni=mly ov] ! l9+ masonry4 ,z ! masonry "w progresses1 ! /rutt+ employ$ previ\sly to support ! walls ( ! excavation has to be remov$4 ,?is "w requires c>e to prev5t accid5t1 & %\ld be plac$ 9 *>ge ( exp]i5c$ me*anics :o are famili> ) its con/ruction1 & c remove x ) ! lea/ damage to ! timb]s1 s t !y may be us$ aga91 & )\t caus+ ! fall ( ! ro( or ! cav+ ( ! sides by remov+ too great a portion ( ! timb]s at "o "t4 ,?ickness ( ,l9+ ,masonry4--,x is obvi\s1 ( c\rse1 t ! masonry l9+ mu/ be ?ick en\gh to support ! pressure ( ! e>? :i* x su/a9s2 b1 z x is impossible to e/imate ^! pressures at all accurately1 x is difficult to say def9itely j :at ?ickness is requir$ 9 any individual case4 ,rank9e gives ! foll[+ =mulas = det]m9+ ! dep?s ( key/one requir$ 9 diff]5t soils3 ,= firm soils 7 r7 d 7#j4ab----71 7 s 7 & = s(t soils1 7 r7 d 7#j4dh----71 7 s 7 :]e d ! dep? ( ! cr[n 9 feet1 r ! rise ( ! ar* 9 feet1 & s ! span ( ! ar* 9 feet4 ,o!r writ]s1 among !m ,pr(essor ,curioni1 attempt to give rational me?ods = calculat+ ! ?ickness ( tunnel l9+2 b !y are all op5 to objection because ( ! am\nt ( hypo!sis requir$ conc]n+ pressures :i* are ( necessity indet]m9ate4 ,!re=e1 to avoid t$i\s & unc]ta9 calculations1 ! eng9e] adopts dim5sions :i* exp]i5ce has prov5 to be ample "u simil> conditions 9 ! pa/4 ,?us we h all gradations 9 ?ickness1 f h>d-rock tunnels requir+ no l9+1 & tunnels ?r\gh rocks :i* simply require a ?9 %ell to protect !m f ! atmosph]e1 to s(t-gr\nd tunnels :]e a masonry l9+ #c ft4 or m 9 ?ickness is employ$4 ,table ,,ii4 %[s ! ?ickness ( masonry l9+ us$ 9 tunnels ?r\gh s(t soils ( v>i\s k9ds4 ,! ?ickness ( ! masonry l9+ is seldom uni=m at all po9ts1 z is indicat$ by ,table ,,ii4 ,figs4 #df & #dg %[ common me?ods ( v>y+ ! ?ickness ( l9+ at diff]5t po9ts1 & are self-explanatory4 ,illu/ration3 ,,figs4 #df & #dg4--,transv]se ,sections ( ,tunnels ,%[+ ,me?ods ( ,increas+ ! ,?ickness ( ! ,l9+ at ,diff]5t ,po9ts4 ,side ,tunnels4--,:5 tunnels are excavat$ by %afts locat$ at "o side ( ! c5t] l9e1 %ort side tunnels or gall]ies are built to connect ! bottoms ( ! %afts ) ! tunnel prop]4 ,^! side tunnels are usually f #cj ft4 to #dj ft4 long1 & are g5]ally made f #ab ft4 to #ad ft4 high1 & ab\t #aj ft4 wide4 ,! excavation1 /rutt+1 & l9+ ( ^! side tunnels are c>ri$ on exactly z !y are 9 ! ma9 tunnel1 ) su* exceptions z ^! %ort l5g?s make possible4 ,table ,,iii4 gives ! ?ickness ( l9+ us$ = side tunnels1 ! figures be+ tak5 f ,european practice4 ,culv]ts4--,! purpose ( culv]ts 9 tunnels is to collect ! wat] :i* seeps into ! tunnel f ! walls & %afts4 ,! culv]t is usually locat$ along ! c5t] l9e ( ! tunnel at ! bottom4 ,9 s(t-gr\nd tunnels x is built ( masonry1 & =ms a "p ( ! inv]t1 b 9 rock tunnels x is ! common practice to cut a *annel 9 ! rock floor ( ! excavation4 ,bo? box & ar* sections are employ$ = culv]ts4 ,! dim5sions ( ! section v>y1 ( c\rse1 ) ! am\nt ( wat] :i* has to be c>ri$ away4 ,! foll[+ are ! dim5sions commonly employ$3 ---------------------------------------- ------------- ,,k9d ,,( ,,culv]t4 ,,height ,,wid? ,,?ickness ,,?ickness ,,9 ,,feet4,,9 ,,feet4,,( ,,walls ,,( ,,cov]+ ,,9 ,,feet4 ,,9 ,,feet4 ---------------------------------------- ------------- ,box culv]t #a to #a4ea to #a4ej4h to #a4b #j4c ,ar* culv]t #a to #a4ea to #a4ej4h to #a4b #j4d ---------------------------------------- ------------- ,x %\ld be und]/ood t ! dim5sions giv5 9 ! table are ^? = ord9>y conditions ( leakage2 :]e l>g] quantities ( wat] are met )1 ! size ( ! culv]ts has1 ( c\rse1 to be enl>g$4 ,to p]mit ! wat] to ent] ! culv]t1 op5+s are provid$ at int]vals along its side2 & ^! op5+s are usually provid$ ) scre5s ( loose /ones :i* *eck ! curr5t1 & cause ! susp5d$ mat]ial to be deposit$ be=e x ent]s ! culv]t4 ,9 cases :]e spr+s are enc\nt]$ 9 excavat+ ! tunnel1 x is necess>y to make special provisions = conf9+ _! outfl[ & conduct+ x to ! culv]t4 ,9 all cases ! culv]ts %\ld be provid$ ) cat* bas9s at int]vals ( f #aej ft4 to #cjj ft41 9 :i* su* susp5d$ matt] z ent]s ! culv]ts is deposit$1 & remov$ ?r\gh cov]$ op5+s ov] ea* bas94 ,at ! ends ( ! tunnel ! culv]t is usually divid$ into two bran*es1 "o runn+ to ! dra9 on ea* side ( ! track4 ,illu/ration3 ,,fig4 #dh4--,refuge ,ni*e 9 ,/4 ,go?>d ,tunnel4 ,ni*es4--,9 %ort tunnels ni*es are employ$ simply z places ( refuge = trackm5 & o!rs dur+ ! pass+ ( tra9s1 & are ( small size4 ,9 long tunnels !y are made l>g]1 & are also employ$ z places = /or+ small tools & supplies employ$ 9 ! ma9t5ance ( ! tunnel4 ,ni*es are simply ar*$ recesses built into ! sides ( ! tunnel1 & l9$ ) masonry2 ,fig4 #dh %[s ?is con/ruction q cle>ly4 ,small refuge ni*es are usually built f #f ft4 to #i ft4 high1 f #c ft4 to #f ft4 wide1 & f #b ft4 to #c ft4 deep4 ,l>ge ni*es design$ = /or+ tools & supplies are made f #aj ft4 to #ab ft4 high1 f #h ft4 to #aj ft4 wide1 & f #ah ft4 to #bd ft4 deep1 & are provid$ ) doors4 ,refuge ni*es are usually spac$ f #fj ft4 to #ajj ft4 ap>t1 :ile ! l>g] /orage ni*es may be locat$ z f> z #cjjj ft4 ap>t4 ,! ni*e con/ruction %[n by ,fig4 #dh is t employ$ on ! ,/4 ,go?>d tunnel4 ,entrances4--,! entrances1 or portals1 ( tunnels usually consi/ ( m or less elaborate masonry /ructures1 dep5d+ ^u ! nature ( ! mat]ial p5etrat$4 ,9 s(t-gr\nd tunnels ext5sive w+ walls are (t5 requir$ to support ! e>? above & at ! sides ( ! entrance2 :ile 9 tunnels ?r\gh rock1 only a masonry portal is requir$1 to give a f9i% to ! "w4 ,(t5 ! eng9e] indulges himself 9 an elaborate ar*itectural design = ! portal masonry4 ,!re is dang] ( c>ry+ su* designs too f> = good ta/e unless c>e is employ$2 & on ?is matt] ! writ] c d no bett] ?an to quote ! rem>ks ( ! late ,mr4 ,fr$]ick ,w4 ,simms 9 8 well-kn[n 8,practical ,tunnel+03 8,! designs = su* con/ructions %\ld be massive to be suitable z approa*es to works pres5t+ ! appe>ance ( gloom1 solidity1 & /r5g?4 ,a light & highly decorat$ /ructure1 h[ev] elegant & well adapt$ = o!r purposes1 w\ld be v unsuitable 9 su* a situation2 x is pla9ness comb9$ ) boldness1 & massiv5ess )\t heav9ess1 t 9 a tunnel entrance con/itutes elegance1 &1 at ! same "t1 is ! mo/ economical40 ,illu/ration3 ,,fig4 #di4--;,ea/ ,portal ( ,hoosac ,tunnel4 ,fig4 #di is an engrav+ f a photograph ( ! ea/ portal ( ! ,hoosac tunnel1 :i* is an especially good design4 ,! portals ( ! ,m\nt ,c5is tunnel 7 built ( samples ( /one enc\nt]$ all along ! l9e ( excavation4 ,! /ones 7 cut & dress$ & utiliz$ = walls & v\ssoirs4 ,! only ornam5t t is usually all[$ on ! portals is ! date ( ! op5+ ( ! tunnel prom95tly cut 9 ! /one above ! ar*4 ,,table ,,ii4 ,%[+ ,?ickness ( ,masonry ,l9+ = ,tunnels ?r\gh ,s(t ,gr\nd4 ---------------------------------------- ------------------------- ,,"* ,,( ,,mat]ial4 ,,key/one4 ,,spr+]s4 ,,inv]t4 ---------------------------------------- ------------------------- ,ft4 ,ft4 ,ft4 ,lam9at$ clay1 fir/ v>iety #b4ae to #c #b4ge to #c4e #a4f to #b4e ,lam9at$ clay1 second v>iety#c to #d4e #c4e to #e4e #b4e to #d ,lam9at$ clay1 ?ird v>iety #d4e to #f4e #e4e to #h4a #d to #d4e ,quicks& #b to #c4bhb to #d4a #a4cc to #b4e ---------------------------------------- ------------------------- ,,table ,,iii4 ,%[+ ,?ickness ( ,masonry ,l9+ = ,side ,tunnels ?r\gh ,s(t ,gr\nd4 ---------------------------------------- --------------------- ,,"* ,,( ,,mat]ial4 ,,key/one4,,spr+]s4 ,,inv]t4 ---------------------------------------- --------------------- ,ft4 ,ft4 ,ft4 ,lam9at$ clay1 fir/ v>iety #a4f to #b4ca4h to #c #a4e to #b ,lam9at$ clay1 second v>iety#b4c to #c #c to #d4ab to #b4f ,lam9at$ clay1 ?ird v>iety #c to #d #d4a to #e #b4f to #c4bi ,quicks& #a4f to #b4ea4c to #b #a4c to #b ---------------------------------------- --------------------- ,,*apt] ,,ix4 ,,tunnels ,,?r\gh ,,h>d ,,rock2 ,,g5]al ,,discussion2 ,,repres5tative ,,me*anical ,,in/allations ,,= ,,tunnel ,,"w4 ,! pres5t high developm5t ( labor-sav+ ma*9]y = excavat+ rock makes ?is mat]ial "o ( ! safe/ & easie/ to tunnel ( any ) :i* ! eng9e] ord9>ily has to deal4 ,to op]ate ?is ma*9]y requires1 h[ev]1 ! developm5t ( a l>ge am\nt ( p[]1 its transmission to consid]able di/ances1 &1 f9ally1 its economical application to ! excavat+ tools4 ,! /&>d rock excavat+ ma*9e is ! p[] drill1 :i* requires ei!r air or hydraulic pressure = its op]ation accord+ to ! special type employ$4 ,"u pres5t conditions1 !re=e1 ! eng9e] is limit$ ei!r to air or wat] "u compression = ! transmission ( 8 p[]4 ,/eam-p[] may be employ$ directly to op]ate p]cussion rock drills2 b ow+ to ! heat & humidity :i* x g5]ates 9 ! conf9$ space :]e ! drills "w1 & because ( o!r reasons1 x is seldom employ$ directly4 ,electric transmission1 :i* (f]s s _m advantages to ! tunnel build]1 9 mo/ respects is l>gely exclud$ f use by ! failure :i* has s f> foll[$ all attempts to apply x to ! op]ation ( rock drills4 ,z matt]s /&1 !re=e1 ! tunnel eng9e] is practically limit$ to /eam & fall+ wat] = ! g5]ation ( p[]1 & to compress$ air & hydraulic pressure = its transmission4 ,:e!r ! eng9e] %\ld adopt wat]-p[] or /eam to g5]ate ! p[] requir$ = 8 excavat+ ma*9]y dep5ds ^u _! relative availability1 co/1 & suitability to ! conditions ( "w 9 ea* p>ticul> case4 ,:]e fuel is pl5tiful & *eap1 & :]e wat]-p[] is n available at a comp>atively reasonable co/1 /eam-p[] w ne>ly always prove ! m economical2 :]e1 h[ev]1 ! rev]se conditions exi/1 :i* is usually ! case 9 a m\nta9\s c\ntry f> f ! coal regions1 & inadequately suppli$ ) transportation facilities1 b ri* 9 m\nta9 torr5ts1 wat]-p[] w g5]ally be ! m economical4 ,9 a succe$+ *apt] ! p[] g5]at+ & transmission plants = a numb] ( rock tunnels are describ$1 & "h only a g5]al consid]ation ( ! subject w be pres5t$4 ,/eam-,p[] ,plant4--,a /eam-p[] plant = tunnel "w %\ld be mu* ! same z a simil> plant else:]e1 except t 9 design+ x ! tempor>y "* ( its "w mu/ be tak5 into consid]ation4 ,?is circum/ance ( its tempor>y employm5t prompts ! omission ( all con/ruction except t necess>y to ! economical work+ ( ! plant dur+ ! p]iod :5 its op]ation is requir$4 ,! p[]-h\se1 ! f\ndations = ! ma*9]y1 & ! g5]al con/ruction & arrangem5t1 %\ld be ! lea/ exp5sive :i* w satisfy ! requirem5ts ( economical & safe op]ation = ! "t requir$4 ,x w (t5 be f\nd m economical z a :ole to op]ate ! ma*9]y ) "s loss ( economy dur+ ! %ort "t t x is 9 use ?an to g to mu* great] exp5se to secure bett] economy f ! ma*9]y by design & con/ruction1 :i* w be ( no fur!r use aft] ! tunnel is complet$4 ,! long] ! plant is to be requir$1 ! ne>] ! con/ruction may economically approa* t ( a p]man5t plant4 ,z reg>ds ! ma*9]y itself1 ^: fur!r usefulness is n limit$ by ! duration ( any s+le piece ( "w1 true economy always dictates ! pur*ase ( ! be/ quality4 ,speak+ 9 a g5]al way1 a /eam-p[] plant = tunnel "w comprises a boil] plant1 a plant ( air compressors ) _! receiv]s1 & an electric light dynamo4 ,:5 hydraulic transmission ( p[] is employ$1 ! air compressors are replac$ by high-pressure pumps2 & :5 electric haul+ is employ$1 "o or m dynamos may be requir$ to g5]ate electricity = p[] purposes1 z well z = light+4 ,9 addition to ! p[] g5]at+ ma*9es prop]1 !re mu/ be ! necess>y pip+ & wir+ = transmitt+ ?is p[]1 &1 ( c\rse1 ! equipm5t ( drills & o!r ma*9es = do+ ! actual excavat+1 haul+1 etc4 ,res]voirs4--,:5 wat]-p[] is employ$1 a res]voir has to be =m$ by damm+ "s ne>-by m\nta9 /ream at a po9t z high z practicable above ! tunnel4 ,! provision ( a res]voir1 in/ead ( draw+ ! wat] directly f ! /ream1 s]ves two important purposes4 ,x insures a cont9u\s supply & con/ant head ( wat] 9 case ( dr\ght1 & also p]mits ! wat] to deposit its s$im5t be=e x is deliv]$ to ! turb9es4 ,! con/ruction ( ^! res]voirs may be ( a tempor>y "*1 or !y may be made p]man5t /ructures1 & utiliz$ aft] con/ruction is complet$ to supply p[] = v5tilation & o!r necess>y purposes4 ,9 ! fir/ case !y are usually de/roy$ aft] con/ruction is f9i%$4 ,9 ei!r case1 x is almo/ unnecess>y to say1 !y %\ld be built amply safe & /rong accord+ to good eng9e]+ practice 9 su* works1 = ! duration ( "t :i* !y are expect$ to exi/4 ,canals & ,pipe ,l9es4--,= convey+ ! wat] f ! res]voirs to ! turb9es1 canals or pipe l9es are employ$4 ,! latt] =m ( conduit is g5]ally pref]able1 x be+ bo? less exp5sive & m easily con/ruct$ ?an ! =m]4 ,x is advisable also to h duplicate l9es ( pipe to r$uce ! possibility ( delay by accid5t or :ile necess>y repairs are be+ made to "o ( ! pipes4 ,! pipe l9es t]m9ate 9 a p5/ock lead+ into ! turb9e *amb]1 & provid$ ) ! necess>y valves = controll+ ! admission ( wat] to ! turb9es4 ,turb9es4--,!re are num]\s =ms ( turb9es on ! m>ket1 b !y may all be class$ ei!r z impulse turb9es or z reaction turb9es4 ,impulse turb9es are ^? 9 :i* ! :ole available en]gy ( ! wat] is conv]t$ into k9etic en]gy be=e ! wat] acts on ! mov+ "p ( ! turb9e4 ,reaction turb9es are ^? 9 :i* only a "p ( ! available en]gy ( ! wat] is conv]t$ into k9etic en]gy be=e ! wat] acts on ! mov+ vanes4 ,impulse turb9es give effici5t results ) any head & quantity ( wat]1 b !y give bett] results :5 ! quantity ( wat] v>ies & ! head rema9s con/ant4 ,reaction turb9es1 on ! contr>y1 give bett] results :5 ! quantity ( wat] rema9s con/ant & ! head v>ies4 ,^! obs]vations indicate 9 a g5]al way ! =m ( turb9e :i* w be/ meet ! p>ticul> conditions 9 ea* case4 ,! numb] ( turb9es requir$1 & _! dim5sions1 w be det]m9$ 9 ea* case by ! numb] ( horse-p[] requir$ & ! quantity ( wat] available4 ,! p[] ( ! turb9es is transmitt$ to ! air compressors or pumps by %aft+ & ge>+4 ,air ,compressors4--,an air compressor is a ma*9e--usually driv5 by /eam1 al?\gh any o!r p[] may be us$--by :i* air is compress$ into a receiv] f :i* x may be pip$ = use4 ,= a detail$ description ( ! v>i\s =ms ( air compressors ! read] %\ld consult ! catalogues ( ! sev]al mak]s & ! v>i\s text-books relat+ to air compression & compress$ air4 ,air compressors1 l o!r ma*9es1 suff] a loss ( p[] by friction4 ,! greate/ loss ( p[]1 h[ev]1 results f ! heat ( compression4 ,:5 air is compress$1 x is heat$1 & its relative volume is increas$4 ,!re=e1 a cubic foot ( hot air 9 ! compressor cyl9d]1 at say1 #fj lbs4 pressure1 does n make a cubic foot ( air at #fj lbs4 pressure aft] cool+ 9 ! receiv]4 ,9 o!r words1 assum+ pressure to be con/ant1 a loss ( volume results due to ! extraction ( ! heat ( compression aft] ! air leaves ! compressor cyl9d]4 ,to r$uce ! am\nt ( ?is loss1 air compressors are design$ ) means to extract ! heat f ! air be=e x leaves ! compressor cyl9d]4 ,air compressors may fir/ be divid$ into two classes1 accord+ to ! means employ$ = cool+ ! air1 z foll[s3 7#a7 ,wet compressors1 & 7#b7 dry compressors4 ,a wet compressor is "o :i* introduces wat] directly into ! cyl9d] dur+ compression1 & a dry compressor is "o :i* admits no wat] to ! air dur+ compression4 ,wet compressors may be subdivid$ into two classes3 7#a7 ,^? :i* inject wat] 9 ! =m ( spray into ! cyl9d] dur+ compression1 & 7#b7 ^? :i* use a wat] pi/on = =c+ ! air into conf9em5t4 ,! foll[+ brief discussion ( ^! v>i\s types ( compressors is bas$ on ! concise practical discussion ( ,mr4 ,w4 ,l4 ,saund]s1 ,m4 ,am4 ,soc4 ,c4 ,e41 9 8,compress$ ,air ,production40 ,! highe/ iso!rmal results are obta9$ by ! injection ( wat] into ! cyl9d]s1 s9ce x is pla9 t ! injection ( cold wat]1 9 ! %ape ( a f9ely divid$ spray1 directly into ! air dur+ compression w l[] ! temp]ature to a great] degree ?an simply to surr\nd ! cyl9d] & p>ts by wat] jackets :i* is ! means ( cool+ adopt$ ) dry compressors4 ,a s]i\s ob/acle to wat] injection1 & t :i* condemns ?is type ( compressor1 is ! influ5ce ( ! inject$ wat] ^u ! air cyl9d] & p>ts4 ,ev5 :5 pure wat] is us$1 ! cyl9d]s we> to su* an ext5t z to produce leakage & to require rebor+4 ,! limitation to ! spe$ ( a compressor is also an important objection4 ,! *ief claim = ! wat] pi/on compressor is t its pi/on is also its cool+ device1 & t ! heat ( compression is absorb$ by ! wat]4 ,wat] is s poor a conductor ( heat1 h[ev]1 t )\t ! addition ( sprays x is safe to say t ?is compressor has sc>cely any cool+ advantages at all s f> z ! cool+ ( ! air dur+ compression is conc]n$4 ,! wat] pi/on compressor op]ates at sl[ spe$ & is exp5sive4 ,its only advantage is t x has no dead spaces4 ,9 ! dry compressor a sacrifice is made 9 ! effici5cy ( ! cool+ device to obta9 l[ fir/ co/1 economy 9 space1 light weight1 high] spe$1 great] durability1 & great] g5]al availability4 ,air compressors are also di/+ui%$ z d\ble act+ & simple act+4 ,!y are simple act+ :5 ! cyl9d] is arrang$ to take 9 air at "o /roke & =ce x out at ! next1 & !y are d\ble act+ :5 !y take 9 & =ce out air at ea* /roke4 ,9 =m compressors may be simple or duplex4 ,!y are simple :5 !y h b "o cyl9d]1 & duplex :5 !y h two cyl9d]s4 ,a /raight l9e or direct act+ compressor is "o 9 :i* ! /eam & air cyl9d]s are set t&em4 ,an indirect act+ compressor is "o 9 :i* ! p[] is appli$ indirectly to ! pi/on rod ( ! air cyl9d] ?r\gh ! m$ium ( a crank4 ,mr4 ,w4 ,l4 ,saund]s writes 9 reg>d to direct & indirect compression z foll[s3-- 8,! exp]i5ce ( ,am]ican manufactur]s1 :i* has be5 m ext5sive ?an t ( o!rs1 has prov$ ! value ( direct compression z di/+ui%$ f indirect4 ,by direct compression is meant ! application ( p[] to resi/ance ?r\gh a s+le /raight rod4 ,! /eam & air cyl9d]s are plac$ t&em4 ,su* ma*9es naturally %[ a l[ friction loss because ( ! direct application ( p[] to resi/ance4 ,?is friction loss has be5 record$ z l[ z #e1 :ile ! be/ practice is ab\t #aj ) ! type :i* conveys ! p[] ?r\gh ! angle ( a crank %aft to a cyl9d] connect$ to ! %aft ?r\gh an additional rod40 ,receiv]s4--,compress$ air is /or$ 9 receiv]s :i* are simply iron tanks capable ( )/&+ a high int]nal pressure4 ,! purpose ( ^! tanks is to provide a res]voir ( compress$ air1 & also to all[ ! air to deposit its moi/ure4 ,f ! receiv]s ! air is convey$ to ! work+s ?r\gh iron pipes1 :i* decrease gradually 9 diamet] f ! receiv]s to ! front4 ,rock ,drills4--,! v>i\s =ms ( rock drills us$ 9 tunnel+ h be5 describ$ 9 ,*apt] ,,iii41 & ne$ n be consid]$ 9 detail "h except to say t ,am]ican eng9e]s usually employ p]cussion drills1 :ile ,european eng9e]s also use rot>y drills ext5sively4 ,a comp>ison betwe5 ^! two types ( drills 0 made 9 excavat+ ! ,a>lb]g tunnel 9 ,au/ria1 :]e ! ,br&t hydraulic rot>y drill 0 us$ at "o end1 & ! ,f]r\x p]cussion drill 0 us$ at ! o!r end4 ,! rock 0 a mica-s*i/4 ,! av]age mon?ly progress 0 #dab ft41 ) a maximum ( #fdf ft41 ) ! rot>y drills1 & an av]age ( #ded ft4 ) ! p]cussion drill4 ,excavation4--,s9ce consid]able "t is requir$ to get ! p[] plant e/abli%$1 ! excavation ( rock tunnels is (t5 begun by h&1 b h& "w is usually cont9u$ = no long] a p]iod ?an is necess>y to get ! p[] plant 9 op]ation4 ,g5]ally speak+1 ! greate/ difficulty is enc\nt]$ 9 excavat+ ! advanc$ drift or head+4 ,bas$ on ! mode ( bla/+ employ$1 !re are two me?ods ( driv+ ! advanc$ gall]y1 kn[n z ! circul> cut & ! c5t] cut me?ods4 ,9 ! fir/ me?od a set ( holes is fir/ drill$ ne> ! c5t] ( ! front 9 su* a mann] t !y inclose a cone ( rock2 ! holes1 />t+ at ! p]imet] ( ! base ( ! cone1 conv]ge t[>d a junction at its apex4 ,seldom m ?an f\r to six holes are compris$ 9 ?is fir/ set4 ,ar\nd ^! fir/ holes are driv5 a r+ ( holes :i* inclose a cyl9d] ( rock1 & if necess>y succe$+ r+s ( holes are driv5 outside ( ! fir/ r+4 ,^! holes are bla/$ 9 ! ord] 9 :i* !y are driv51 ! fir/ set tak+ out a cone ( rock1 ! second set enl>g+ ?is cone to a cyl9d]1 & ! o!r sets enl>g+ ?is cyl9d] to ! requir$ dim5sions ( ! head+4 ,! numb] ( holes1 h[ev]1 v>ies ) ! quality ( rock & !y are seldom driv5 deep] ?an #d or #e ft4 ,?is me?od ( excavat+ ! head+1 :i* is commonly foll[$ by ,european eng9e]s1 is illu/rat$ 9 ,figs4 #ej to #eb4 ,9 ^! figures are indicat$ ! numb] ( holes 9 ea* r\nd & ! sequ5ce ( r\nds = ! s(t1 m$ium & h>d rock1 z us$ 9 ! ,tur*9o tunnel ( ! ,g5ova ,ovada ,a/i l9e ( ! ,m$it]ranean ,railway ( ,italy4 ,! head+ 0 ab\t #i ft4 squ>e1 & five sets ( holes 7 us$ 9 bla/+1 ! dep?s be+ #c4ia1 #d4bf & #d4f ft4 = s(t1 m$ium & h>d rock1 respectively1 & ! am\nt ( dynamite consum$ 0 #b4ch1 #c4ia & #e4a p\nds p] cubic y>d = ! ?ree classes ( rock4 ,illu/ration3 9 ,s(t ,rock 9 ,m$ium ,rock 9 ,h>d ,rock ,,figs4 #ej to #eb4--;,arrangem5t ( ,drill ,holes 9 ! ,head+ ( ,tur*9o ,tunnel4 ,illu/ration3 ,,figs4 #ec & #ed4--;,arrangem5t ( ,drill ,holes 9 ! ,head+ ( ! ,=t ,george ,tunnel4 ,9 ! c5t]-cut me?od1 :i* is ! "o commonly employ$ 9 ,am]ica1 ! holes are arrang$ 9 v]tical r[s1 & are driv5 f #h to #aj ft4 deep4 ,fig4 #ec %[s ! arrangem5t ( ! holes1 & ! me?od ( bla/+ !m1 z us$ 9 ! excavation ( ! head+ = ! ,=t ,george tunnel ( ! ,new ,york rapid transit4 ,! two c5t] r[s ( holes conv]ge t[>d ea* o!r s z to take out a w$ge ( rock2 o!rs are bor$ /raight1 or p>allel1 ) ! v]tical plane ( ! tunnel4 ,^? bor$ ar\nd ! p]imet] are driv5 ei!r outw>d or upw>d1 accord+ z !y are locat$1 close to ! sides or ro( ( ! tunnel4 ,9 ?is case1 ! holes ( ! c5t] cut 7 driv5 #i ft4 deep1 :ile all ! o!r holes 7 bor$ to a dep? ( #h ft4 ,! wid? ( ! advanc$ gall]y or head+ dep5ds ^u ! quality ( ! rock4 ,9 h>d rock ,am]ican eng9e]s give x ! full wid? ( ! tunnel section2 b ?is _c be done 9 loose or fissur$ rock1 :i* has to be support$1 ! head+s "h be+ usually made ab\t #h #h ft4 ,! wid] head+ is always pref]able1 :]e x is possible1 s9ce m room is available = remov+ ! rock1 & deep] holes c be bor$ & bla/$4 ,! important rle play$ by ! p[] plant & o!r me*anical in/allations 9 con/ruct+ tunnels ?r\gh rock has already be5 m5tion$4 ,9 "s me?ods ( s(t-gr\nd tunnel+1 & p>ticul>ly 9 s(t-gr\nd subaque\s tunnel+1 x is also (t5 necess>y to employ a me*anical in/allation b slightly inf]ior 9 size & co/ to ^? us$ 9 tunnel+ rock4 ,x is propos$ to describe v briefly "h a few typical individual plants ( ?is "*1 :i* w 9 "s respects give a bett] idea ( ?is phase ( tunnel "w ?an ! m g5]al descriptions4 ,rock ,tunnels4--,! tunnels select$ to illu/rate ! me*anical in/allations employ$ 9 tunnel+ ?r\gh rock are3 ,! ,mont ,c5is1 ,hoosac ,tunnel1 ! ,cascade ,tunnel1 ! ,niag>a ,falls ,p[] ,tunnel1 ! ,palisades ,tunnel1 ! ,croton ,aqu$uct ,tunnel1 ! ,/rickl] ,tunnel 9 ,am]ica1 & ! ,graveholz ,tunnel & ! ,sonn/e9 ,tunnel 9 ,europe4 ,9 addition !re w be f\nd 9 ano!r *apt] ( ?is book a description ( ! me*anical in/allations at ! ,/4 ,go?>d1 ,p5nsylvania & o!r tunnels4 ,mont ,c5is ,p[] ,plant4--,! me*anical in/allation consi/$ ( ! ,sommeili] air compressors built ne> ! portals4 ,! ,sommeili] compressors1 ,mr4 ,w4 ,l4 ,saund]s says1 7 op]at$ z a ram1 utiliz+ a natural head ( wat] to =ce air at #hj lbs4 pressure into a receiv]4 ,! column ( wat] conta9$ 9 ! long pipe on ! side ( ! hill 0 />t$ & /opp$ automatically by valves controll$ by eng9es4 ,! weight & mom5tum ( ! wat] =c$ a volume ( air ) su* a %ock aga9/ ! dis*>ge valve t x 0 op5$1 & ! air 0 dis*>g$ into ! tank2 ! valve 0 !n clos$1 ! wat] *eck$2 a portion ( x 0 all[$ to dis*>ge1 & ! space 0 fill$ ) air1 :i* 0 9 turn =c$ into ! tank4 ,only #gc ( ! p[] ( ! wat] 0 available1 #bg be+ lo/ by ! friction ( ! wat] 9 ! pipes1 valves1 b5ds1 etc4 ,( ! #gc ( net "w1 #di4d 0 consum$ 9 ! p]=ators1 & #bc4f 9 a dummy eng9e = work+ ! valves ( ! compressors & = special v5tilation4 ,! compress$ air 0 convey$ f ea* end ?r\gh a ca/-iron pipe #g 94 9 diamet]1 up to ! front ( ! excavation4 ,! jo9ts ( ! pipes 7 made ) turn$ faces1 groov$ to receive a r+ ( oakum :i* 0 tightly screw$ & compress$ into ! jo9t4 ,to asc]ta9 ! am\nt ( leakage ( ! pipes1 !y & ! tanks 7 fill$ ) air compress$ to #f atmosph]es1 & ! ma*9es /opp$2 aft] #ab h\rs ! pressure 0 r$uc$ to #e4g atmosph]es1 or to #ie ( ! orig9al pressure4 ,sommeili]'s p]cussion drill+ ma*9es 7 us$ 9 ! excavation ( ?is tunnel4 ,!y 7 provid$ ) #h or #aj drills act+ at ! same "t1 & m\nt$ on c>riages runn+ on tracks4 ,^! 7 )drawn to a safe place dur+ ! bla/+1 & advanc$ aga9 aft] ! brok5 rock 0 remov$ f ! front & ! new tracks laid4 ,ma*9e %ops 7 built at bo? ends ( ! tunnel = build+ & repair+ ! drill+ ma*9es1 bits1 tools1 etc4 ,a gas factory 0 built at ea* end = light+ purpose4 ,hoosac ,tunnel4--,! ,hoosac tunnel on ! ,fit*burg ,r4,r4 9 ,massa*usetts is #be1jjj ft4 long1 & ! longe/ tunnel 9 ,am]ica4 ,! mat]ial ?r\gh :i* ! tunnel 0 driv5 0 *iefly h>d granitic gneiss1 conglom]ate1 & mica-s*i/ rock4 ,! excavation 0 conduct$ f ! entrances & "o %aft1 ! wide head+ & s+le-b5* me?od be+ employ$1 ) ! c5t]-cut sy/em ( bla/+ :i* 0 "h us$ = ! fir/ "t4 ,! tunnel 0 begun 9 #ahed1 & cont9u$ by h& until #ahff1 :5 ! me*anical plant 0 in/all$4 ,mo/ ( ! p>ticul> ma*9es employ$ h n[ become obsolete1 b z !y 7 ! fir/ ma*9es us$ = rock tunnel+ 9 ,am]ica !y des]ve m5tion4 ,! drills us$ 7 ,burleigh p]cussion drills1 op]at$ by compress$ air4 ,six ( ^! drills 7 m\nt$ on a s+le c>riage1 & two c>riages 7 us$ at ea* front4 ,! air to op]ate ^! drills 0 suppli$ by air compressors op]at$ by wat]-p[] at ! portals & /eam-p[] at ! %aft4 ,! air compressors consi/$ ( f\r horizontal s+le-act+ air cyl9d]s ) poppet valves & wat] injection4 ,! compressors 7 design$ by ,mr4 ,?omas ,deane1 ! *ief eng9e] ( ! tunnel4 ,palisades ,tunnel4--,! ,palisades tunnel 0 con/ruct$ to c>ry a d\ble track railway l9e ?r\gh ! ridge ( rocks bord]+ ! we/ bank ( ! ,hudson ,riv] & kn[n z ! ,palisades4 ,x 0 locat$ ab\t opposite #aaf? ,/4 9 ,new ,york ,city4 ,! mat]ial p5etrat$ 0 a h>d trap rock v full ( seams 9 places1 :i* caus$ l>ge fragm5ts to fall f ! ro(4 ,! excavation 0 made by a s+le wide head+ & b5*1 employ+ ! c5t]-cut me?od ( bla/+ ) eight c5t] holes & #af side holes = ! #g #ah ft4 head+4 ,+]soll-,s]geant #b 94 drills 7 us$1 f\r 9 ea* head+ & six on ea* b5*1 & #cj ft4 p] #aj h\rs 0 consid]$ good "w = "o drill4 ,! p[]-plant 0 situat$ at ! we/ portal ( ! tunnel1 & ! p[] 0 transmitt$ by electricity & compress$ air to ! middle %aft & ea/ portal work+s4 ,! plant consi/$ ( eight #ajj ,h4 ,p4 boil]s1 furni%+ /eam to f\r ,r& duplex #ah #bb 94 air compressors1 & an eng9e runn+ a #cj arc light dynamo4 ,! compress$ air 0 c>ri$ ov] ! ridge by pipes1 v>y+ f #aj ins4 to #e ins4 9 diamet]1 to ! %aft & to ! ea/ portal1 & 0 us$ = op]at+ ! hoi/+ eng9es z well z ! drills at ^! work+s4 ,inside ! tunnel1 specially design$ d]rick c>s 7 employ$ to h&le l>ge /ones1 !y be+ also op]at$ by compress$ air4 ,?is c> ran on a c5t] track1 :ile ! muck+ c>s ran on side tracks1 & x 0 employ$ to lift ! bodies ( ! c>s f ! trucks1 place !m close to ! front1 be+ work$ :]e l>ge /one c\ld be roll$ into !m1 & return !m to ! trucks = removal4 ,9 addition to h&l+ ! c> bodies ! d]rick 0 us$ to lift heavy /ones4 ,! haul+ 0 done fir/ by horse-p[]1 & lat] by dummy locomotives4 ,croton ,aqu$uct ,tunnel4--,9 ! con/ruction ( ! ,croton ,aqu$uct = ! wat] supply ( ,new ,york ,city1 a tunnel #ca miles long 0 built1 runn+ f ! ,croton ,dam to ! ,gate ,h\se at #ace? ,/4 9 ,new ,york ,city4 ,! section ( ! tunnel v>ies 9 =m1 b is g5]ally ei!r a circul> or a horse%oe section4 ,9 all cases ! section 0 design$ to h a capacity = ! fl[ ( wat] equal to a cyl9d] #ad ft4 9 diamet]4 ,to drive ! tunnel1 #dj %afts 7 employ$4 ,! mat]ial p5etrat$ 0 ( almo/ e "*1 f quicks& to granitic rock1 b ! bulk ( ! "w 0 9 rock ( "s "*4 ,! excavation 9 rock 0 conduct$ by ! wide head+ & b5* me?od1 employ+ ! c5t]-cut me?od ( bla/+4 ,f\r air drills1 m\nt$ on two d\ble-arm columns 7 employ$ 9 ! head+4 ,! drills = ! b5* "w 7 m\nt$ on tripods4 ,/eam-p[] 0 us$ exclusively = op]at+ ! compressors1 hoi/+ eng9es1 v5tilat+ fans & pumps2 b ! size & k9d ( boil]s us$1 z well z ! k9d & capacity ( ! ma*9es :i* !y op]at$1 v>i$ greatly1 s9ce a sep>ate p[]-plant 0 employ$ = ea* %aft ) a few exceptions4 ,a description ( ! plant at "o ( ! %afts w give an indication ( ! size & "* ( ^? at ! o!r %afts1 & = ?is purpose ! plant at %aft #aj has be5 select$4 ,at %aft #aj /eam 0 provid$ by two ,+]soll boil]s ( #hj ,h4 ,p4 ea*1 & by a small upright boil] ( #h ,h4 ,p4 ,!re 7 two #ah #cj 94 ,+]soll air compressors pump+ into two #db 94 #aj ft4 & two #db 94 #ab ft4 ,+]soll receiv]s4 ,9 ! excavation !re 7 twelve #c 94 & six #c 94 ,+]soll drills1 f\r drills m\nt$ on two d\ble arm columns be+ us$ on ea* head+1 & ! rema9d] m\nt$ on tripods be+ us$ on ! b5*4 ,two ,dickson cages op]at$ by "o #ab #ab 94 ,dickson rev]sible d\ble hoi/+ eng9e provid$ transportation = mat]ial & supplies up & d[n ! %aft4 ,a ,?omson-,h\/on t5-light dynamo op]at$ by a ,lidg]wood eng9e provid$ light4 ,dra9age 0 effect$ by means ( two ,no4 #i & "o ,no4 #f ,cam]on pumps4 ,at ?is p>ticul> %aft ! air exhau/$ f ! drills gave ample v5tilation1 especially :5 aft] ea* bla/ ! smoke 0 cle>$ away by a jet ( compress$ air4 ,9 o!r work+s1 h[ev]1 :]e ?is means ( v5tilation 0 n suffici5t1 ,bak] bl[]s 7 g5]ally employ$4 ,/rickl] ,tunnel4--,! ,/rickl] tunnel = ! wat] supply ( ,colorado ,spr+s1 ,col41 is #fdda ft4 long ) a section ( #d ft4 #g ft4 ,x p5etrates ! ridge connect+ ,pike's ,peak & ! ,big ,horn ,m\nta9s1 at an elevation ( #aa1edj ft4 above sea level4 ,! mat]ial p5etrat$ is a co>se porphyritic granite & mora9al dbris1 ! portion ?r\gh ! latt] mat]ial be+ l9$4 ,! me*anical in/allation consi/$ ( a wat]-p[] electric plant op]at+ air compressors4 ,! wat] f ,buxton ,creek hav+ a fall ( #bdjj ft4 0 utiliz$ to op]ate a #cf 94 #bbj ,h4 ,p4 ,pelton wat]-:eel1 :i* op]at$ a #aej ,k4 ,w4 ?ree-phase g5]ator4 ,f ?is g5]ator a #cejj volt curr5t 0 transmitt$ to ! ea/ portal ( ! tunnel1 :]e a /ep-d[n trans=m] r$uc$ x to a #bbj volt curr5t to ! motor4 ,! transmission l9e consi/$ ( ?ree ,no4 #e wires c>ri$ on cross-arm poles & provid$ ) lightn+ arre/]s at int]vals4 ,! plant at ! ea/ portal ( ! tunnel consi/$ ( a #ge ,h4 ,p4 electric motor1 driv+ a #ge ,h4 ,p4 air compressor1 & ( small motors to drive a ,/urtevant bl[] = v5tilation1 to run ! blacksmi? %op1 & to light ! tunnel1 %op1 & y>ds4 ,f ! compressor air 0 pip$ into ! tunnel at ! ea/ end1 & also ov] ! m\nta9 to ! we/ portal work+s4 ,two drills 7 us$ at ea* end1 & ! air 0 also us$ = op]at+ d]ricks & o!r ma*9]y4 ,= remov+ ! spoil a trolley c>ri] sy/em 0 employ$4 ,a longitud9al timb] 0 fa/5$ to ! tunnel ro(1 directly 9 ! apex ( ! ro( ar*4 ,?is timb] c>ri$ by means ( hang]s a /eel b> trolley rail on :i* ! c>riages ran4 ,outside ( ! portal ?is rail =m$ a loop1 s t ! c>riage c\ld pass ar\nd ! loop & be tak5 back to ! work+ face4 ,ea* c>riage c>ri$ a /eel span ( #a cu4 ft4 capacity1 s susp5d$ t by means ( a tripp+ device x 0 automatically dump$ :5 ! prop] po9t on ! loop 0 rea*$4 ,niag>a ,falls ,p[] ,tunnel4--,! tail-race tunnel built to c>ry away ! wat] dis*>g$ f ! turb9es ( ! ,niag>a ,falls ,p[] ,co41 has a horse-%oe section #ai #ba ft4 & a l5g? ( #fgjj ft4 ,x 0 driv5 ?r\gh rock f ?ree %afts by ! c5t]-cut me?od ( bla/+4 ,9 s9k+ %aft ,no4 #j v little wat] 0 enc\nt]$1 b at %afts ,nos4 #a & #b an infl[ ( #hjj gallons & #fjj gallons p] m9ute1 respectively1 0 enc\nt]$4 ,! pr9cipal plant 0 locat$ at %aft ,no4 #b1 & consi/$ ( eight #ajj ,h4,p4 boil]s1 ?ree #ah #cj 94 ,r& duplex air compressors1 a ,?omson-,h\/on electric-light plant1 & a sawmill ) a capacity ( #bj1jjj ft4 ,b4 ,m4 p] day4 ,! %afts 7 fitt$ ) ,otis automatic hoi/+ eng9es1 ) d\ble cages at %afts ,nos4 #a & #b1 & a s+le cage at %aft ,no4 #j4 ,! drills us$ 7 #be ,r& drills & ?ree ,+]soll-,s]geant drills4 ,! pump+ plant at %aft ,no4 #b consi/$ ( f\r ,no4 #g & "o ,no4 #i ,cam]on pumps1 & t at %aft ,no4 #b consi/$ ( two ,no4 #g & two ,no4 #i ,cam]on pumps & ?ree ,sn[ pumps4 ,an auxili>y boil] plant consi/+ ( two #fj ,h4 ,p4 boil]s 0 locat$ at %aft ,no4 #a1 & ano!r1 consi/+ ( "o #ge ,h4 ,p4 boil]1 0 locat$ at %aft ,no4 #j4 ,cascade ,tunnel4--,! ,cascade tunnel 0 built 9 #ahhf-hh to c>ry ! d\ble tracks ( ! ,nor!rn ,pacific ,ry4 ?r\gh ! ,cascade ,m\nta9s 9 ,wa%+ton4 ,x is #ihej ft4 long ) a cross-section #af ft4 wide & #bb ft4 high1 & is l9$ ) masonry4 ,! mat]ial p5etrat$ 0 a basaltic rock1 ) a dip ( ! /rata ( ab\t #e4 ,! rock 0 excavat$ by a wide head+ & "o b5*1 us+ ! c5t]-cut sy/em ( bla/+4 ,a /rutt+ consi/+ ( five-segm5t timb] ar*es c>ri$ on side po/s1 spac$ f #b ft4 to #d ft4 ap>t1 & hav+ a ro( lagg+ ( #d #f 94 timb]s pack$ above ) cord-wood4 ,! me*anical plant ( ! tunnel is ( p>ticul> int]e/1 because ( ! fact t all ! ma*9]y & supplies _h to be haul$ f #hb to #hg miles by teams1 ov] a road cut ?r\gh ! =e/s cov]+ ! m\nta9 slopes4 ,?is "w requir$ f ,feb4 #bb to ,july #ae1 #ahhf1 to p]=m4 ,9 _m places ! grades 7 s /eep t ! wagons _h to be haul$ by block & tackle4 ,! plant consi/$ ( five eng9es1 two wat]-:eels1 five air compressors1 eight #gj ,h4 ,p4 /eam-boil]s1 f\r l>ge exhau/ fans1 two complete electric arc-light+ plants1 two fully equipp$ ma*9e-%op outfits1 #cf air drills1 two locomotives1 #fj dump c>s1 & two sawmill outfits1 ) ! necess>y accessories = ^! v>i\s ma*9es4 ,?is plant 0 divid$ ab\t equally betwe5 ! two ends ( ! tunnel4 ,! co/ ( ! plant & ( ! "w ( gett+ x into position 0 #abe1jjj4 ,graveholz ,tunnel4--,! ,graveholz tunnel on ! ,b]g5 ,railway 9 ,norway is notable z be+ ! longe/ tunnel 9 nor!rn ,europe1 & also z be+ built = a s+le-track n>r[-gauge railway4 ,?is tunnel is #ag1djj feet long1 & is locat$ at an elevation ( #bijj feet above sea-level4 ,only ab\t #c ( ! l5g? ( ! tunnel is l9$4 ,! me*anical in/allation consi/s ( a turb9e plant op]at+ ! v>i\s ma*9es4 ,!re are two turb9es ( #ajj ,h4 ,p4 & #abj ,h4 ,p4 tak+ wat] f a res]voir on ! m\nta9 slope1 & furni%+ #bbj ,h4 ,p41 :i* is di/ribut$ ab\t z foll[s3 ,bor+-ma*9es1 #fj ,h4 ,p42 v5tilation1 #cj to #dj ,h4 ,p42 electric locomotives1 #ae ,h4 ,p42 ma*9e %op1 #ae ,h4 ,p42 electric-light+ dynamo1 #be ,h4 ,p42 electric drills1 ! surplus1 or "s #dj ,h4 ,p4 ,! bor+-ma*9es & electric drills w be op]at$ by ! small] #ajj ,h4 ,p4 turb9e4 ,sonn/e9 ,tunnel4--,! ,sonn/e9 tunnel 9 ,g]many is p>ticul>ly int]e/+ because ( ! exclusive use ( ,br&t rot>y drills4 ,! tunnel 0 driv5 ?r\gh dolomite & h>d lime/one by means ( a drift & two side gall]ies4 ,! dim5sions ( ! drift 7 #g #g ft4 ,! p[] plant consi/$ ( two /eam pressure pumps1 "o accumulator1 & f\r drills4 ,! /eam-boil] plant1 9 addition to op]at+ ! pumps1 also suppli$ p[] = op]at+ a rot>y pump = dra9age & a bl[] = v5tilation4 ,! hydraulic pressure requir$ 0 #ge atmosph]es 9 ! dolomite1 & f #he to #ajj atmosph]es 9 ! lime/one4 ,! drift 0 excavat$ ) five #c 94 holes1 "o be+ plac$ at ! c5t] & driv5 p>allel to ! axis ( ! tunnel1 & f\r be+ plac$ at ! corn]s ( a rectangle correspond+ to ! sides ( ! drift1 & driv5 at an angle div]g+ f ! c5t] hole4 ,! av]age dep?s ( ! holes 7 #d4c ft41 & ! effici5cy ( ! drills 0 #a 94 p] m9ute4 ,"o drill 0 employ$ at ea* front1 & 0 op]at$ by a ma*9i/ & two help]s1 :o work$ eight-h\r %ifts1 ) a bla/ betwe5 %ifts at fir/1 & lat] twelve-h\r %ifts1 ) a bla/ betwe5 %ifts4 ,! #bd h\rs ( ! two %ifts 7 divid$ z foll[s3 bor+ ! holes1 #aj4g h\rs2 *>g+ ! holes1 #a4a h\rs2 remov+ ! spoil1 #aa4g h\rs2 *ang+ %ifts1 #j4e h\r4 ,! av]age progress p] day = ea* ma*9e 0 #f4g ft4 ,! total co/ ( ! plant 0 #ag1dej4 ,/4 ,clair ,riv] ,tunnel4--,! subm>9e d\ble-track railway tunnel "u ! ,/4 ,clair ,riv] = ! ,gr& ,trunk ,ry4 is #hejj ft4 long1 & 0 driv5 ?r\gh clay by means ( a %ield1 z describ$ 9 ! succe$+ *apt] on ! %ield sy/em ( tunnel+4 ,! me*anical plant in/all$ = prosecut+ ! "w 0 v complete4 ,to furni% /eam to ! air compressors1 pumps1 electric-light eng9es1 hoi/+-eng9es1 etc41 a /eam-plant 0 provid$ on ea* side ( ! riv]1 consi/+ ( ?ree #gj ,h4 ,p4 & f\r #hj ,h4 ,p4 ,scot* portable boil]s4 ,! air-compressor plant at ea* end consi/$ ( two #bj #bd 94 ,+]soll air compressors4 ,to furni% light to ! work+s1 two #ajj c&le-p[] ,edison dynamos 7 in/all$ on ! ,am]ican side1 & two ,ball dynamos ( ! same size 7 in/all$ on ! ,canadian side4 ,! dynamos on bo? sides 7 driv5 by ,arm+ton ,sims eng9es4 ,^! dynamos furni%$ light to ! tunnel work+s & to ! ma*9e-%ops & p[]-plant at ea* end4 ,root bl[]s ( #aj1jjj cu4 ft4 p] m9ute capacity provid$ v5tilation4 ,! pump+ plant consi/$ ( "o set ( pumps in/all$ = p]man5t dra9age1 & ano!r set in/all$ = dra9age dur+ con/ruction1 & also to rema9 9 place z a "p ( ! p]man5t plant4 ,! latt] set consi/$ ( two #ejj gallon ,wor?+ton duplex pumps set fir/ outside ( ea* air lock1 clos+ ! ends ( ! riv] portion ( ! tunnel4 ,= p]man5t dra9age1 a dra9age %aft 0 sunk on ! ,canadian side ( ! riv]1 & connect$ ) a pump at ! bottom ( ! op5-cut approa*4 ,9 ?is %aft 7 plac$ a v]tical1 direct-act+1 comp\nd-cond5s+ pump+ eng9e ) two #ai 94 high-pressure & two #cc 94 l[-pressure cyl9d]s ( #bd 94 /roke1 connect$ to d\ble-act+ pumps ) a capacity ( #cjjj gallons p] m9ute1 & also two duplex pumps ( #ejj gallons capacity p] m9ute4 ,= p]man5t dra9age on ! ,am]ican side1 f\r ,wor?+ton pumps ( #cjjj gallons' capacity 7 in/all$ 9 a pump-h\se set back into ! slope ( ! op5-cut approa*4 ,= ! p]man5t dra9age ( ! tunnel prop] two #djj gallon pumps 7 plac$ at ! l[e/ po9t ( ! tunnel grade4 ,spoil com+ f ! tunnel prop] 0 hoi/$ to ! top ( ! op5 cut by d]ricks op]at$ by two #ej ,h4 ,p4 ,lidg]wood hoi/+-eng9es4 ,! pressure pump+ plant = supply+ wat] to ! hydraulic %ield-jacks at ea* end ( ! tunnel consi/$ ( duplex direct-act+ eng9es ) #ab 94 /eam cyl9d]s & #a 94 wat] cyl9d]s1 supply+ wat] at a pressure ( #bjjj lbs4 p] sq4 94 ,,*apt] ,x4 ,,tunnels ,,?r\gh ,,h>d ,,rock 7,cont9u$74 ,,excavation ,,by ,,drifts3 ,,! ,,simplon ,,& ,,murray ,,hill ,,tunnels4 ,illu/ration3 ,,fig4 #ee4--;,diagram ,%[+ ,sequ5ce ( ,excavations 9 ,drift ,me?od ( ,tunnel+ ,rock4 ,g5]al ,description4--,! me?od ( tunnel+ ?r\gh h>d rock by drifts is pref]r$ by ,european eng9e]s4 ,all ! great ,alp9e tunnels1 f ! ,mont ,c5is tunnel to ! ,simplon1 are examples ( tunnel+ by drifts4 ,9 ?is me?od ! sequ5ce ( excavation is %[n diagrammatically by ,fig4 #ee4 ,! "w beg9s by excavat+ a drift close to ! floor ( ! propos$ tunnel 7z %[n 9 ! c5t] ( ! figure7 & f> 9 advance ( ! excavation ( any o!r "p4 ,! section m>k$ #b is next remov$ & /ill lat] ! portions m>k$ #c4 ,!n ) ! removal ( ! p>ts m>k$ #d ! :ole section ( ! tunnel w be op54 ,! drift is usually /rutt$ by means ( side po/s c>ry+ a cap-piece plac$ at int]vals1 & hav+ a ceil+ ( longitud9al planks re/+ on ! successive caps4 ,9 h>d rock ! ro( ( ! section does n1 z a rule1 require regul> /rutt+1 occasional supports be+ plac$ at int]vals to prev5t ! fall ( isolat$ fragm5ts3 ,:5 ! rock is dis9tegrat$ or full ( seams1 a regul> /rutt+ may be necess>y1 & ?is may be ei!r longitud9al or polygonal 9 type4 ,:5 longitud9al /rutt+ is employ$1 a sill is laid across ! ro( ( ! drift1 & ^u ?is are set up two /ruts conv]g+ t[>d ! top & support+ a cap-piece close to ! ro(4 ,on ?is cap-piece are plac$ ! fir/ longitud9al cr[n b>s c>ry+ transv]se pol+-bo>ds4 ,additional props /&+ on ! sill & radiat+ outw>d are ins]t$ z p>ts ,no4 #c are excavat$4 ,^! radial props c>ry longitud9al b>s :i* 9 turn support transv]se pol+-bo>ds4 ,:5 polygonal /rutt+ is us$1 x may take ! =m ( ?ree or five segm5t ar*es ( heavy timb]s4 ,9 h>d rock tunnels1 z a rule1 !re is no dang] ( cav+ 9 because ( heavy pressures1 & ! :ole section is left op5 = "s "t be=e x is l9$4 ,! l9+ may be ( concrete masonry1 b 9 _m long tunnels1 excavat$ ?r\gh h>d rock1 ! side walls are l9$ ) rubble masonry & ! ar* ) brick1 &1 9 "s in/ances1 ev5 ! ar* has be5 l9$ ) rubble masonry4 ,) skilful labor]s at h& ! rubble masonry l9+ has prov$ mo/ effici5t & economical1 because ! rock is utiliz$ z x is excavat$ )\t any fur!r op]ation4 ,concrete1 h[ev]1 is m ext5sively employ$ = l9+ tunnels ?an any o!r mat]ial4 ,tunnels excavat$ by drifts enable simple means ( haul+ to be employ$1 & ?is is "o ( ! reasons :y ! me?od f9ds s mu* favor ) ,european eng9e]s4 ,! tracks are laid along ! floor ( ! drift1 & c>ry all ! spoil f p>ts ,nos4 #b1 #c1 & #d1 z well z f ! front ( ! drift itself4 ,z fa/ z ! full section is complet$1 ?is s+le track 9 ! drift is replac$ by two tracks runn+ close to ! sides ( ! tunnel1 or by a broad-gauge track ) a ?ird rail4 ,,! ,,simplon ,,tunnel4#h ,be=e ent]+ ^u a description ( ! con/ructive details ( ?is1 ! longe/ railway tunnel 9 ! _w1 x may be well to give a g5]al idea ( ! und]tak+4 ,_m s*emes = ! connection ( ,italy & ,switz]l& by a railway ne> ! ,simplon ,road ,pass h be5 devis$1 includ+ "o involv+ no great l5g? ( und]gr\nd "w1 ! l9e m\nt+ by /eep gradi5ts & %>p curves4 ,! pres5t s*eme1 put =w>d 9 #ahha by ! ,jura-,simplon ,ry4 ,co41 consi/s broadly ( pi]c+ ! ,alps betwe5 ,brigue1 ! pres5t railway t]m9us 9 ! ,rhone ,valley1 & ,iselle1 9 ! gorge ( ! ,div]ia1 on ! ,italian side1 f :i* village ! railway w desc5d to ! exi/+ s\!rn t]m9us at ,domo d',ossola1 a di/ance ( ab\t #aa miles4 #h ,ab/ract f a pap] read be=e ! ,in/itution ( ,civil ,eng9e]s by ,*>les ,b4 ,fox1 ,jan4 #bf1 #aijj4 ,9 conjunction ) ?is s*eme a second tunnel is propos$1 to pi]ce ! ,b]nese ,alps "u ! ,lts*5 ,pass f ,mit?olz to a po9t ne> ,turtman 9 ! ,rhone ,valley2 & ?us1 in/ead ( ! long dt\r by ,lausanne & ! ,lake ( ,g5eva1 !re w be an almo/ direct l9e f ,b]ne to ,milan via ,?un1 ,brigue1 & ,domo d',ossola4 ,/>t+ f ,brigue1 ! new l9e1 runn+ g5tly up ! valley = #a miles1 w1 on acc\nt ( ! proximity ( ! ,rhone1 :i* has already be5 slightly div]t$1 ent] ! tunnels on a curve to ! "r ( #ajej ft4 radius4 ,at a di/ance ( #aec y>ds f ! entrance1 ! /raight portion ( ! tunnel comm5ces1 & ext5ds = #ab miles4 ,! l9e !n curves to ! left ) a radius ( #acaa ft4 be=e em]g+ on ! left bank ( ! ,div]ia4 ,comm5c+ at ! nor!rn entrance1 a gradi5t ( #a 9 #ejj 7! m9imum = effici5t dra9age7 rises = a l5g? ( #e miles to a level l5g? ( #eej y>ds 9 ! c5t]1 & !n a gradi5t ( #a 9 #adc desc5ds to ! ,italian side4 ,on ! way to ,domo d',ossola "o helical tunnel w be necess>y1 z has be5 c>ri$ out on ! ,/4 ,go?>d4 ,!re w be ev5tually two p>allel tunnels hav+ _! c5t]s #ef ft4 ap>t1 ea* c>ry+ "o l9e ( way2 b at ! pres5t "t only "o head+1 t kn[n z ,no4 #a1 is be+ excavat$ to full size1 ,no4 #b be+ left1 masonry l9$ :]e necess>y1 = future developm5ts4 ,by means ( cross head+s e #bbj yds4 ! problems ( transport & v5tilation are greatly facilitat$1 z w be se5 lat]4 ,z bo? entrances are on curves1 a small 8gall]y ( direction0 is necess>y1 to all[ corrections ( al9em5t to be made direct f ! two obs]vatories on ! axis ( ! tunnel4 ,! outside in/allations are z ne>ly 9 duplicate z circum/ances w all[1 & consi/ ( ! necess>y (fices1 work%ops1 eng9e-%$s1 p[]-h\ses1 smi?ies1 & ! num]\s build+s entail$ by an important eng9e]+ s*eme4 ,great c>e is tak5 t ! m9]s & m5 work+ 9 ! tunnel %all n suff] f ! sudd5 *ange f ! w>m head+s to ! cold ,alp9e air outside2 & = ?is purpose a l>ge build+ is 9 c\rse ( erection1 :]e !y w be able to take (f _! damp work+ clo!s1 h a hot & cold d\*e1 put on a w>m dry suit1 & obta9 refre%m5ts at a mod]ate co/ be=e return+ to _! homes4 ,in/ead ( ea* man hav+ a lock] 9 :i* to /[ 8 clo!s1 a p]fect =e/ ( cords hangs d[n f ! wood5 ceil+1 #be ft4 above floor-level1 ea* cord pass+ ov] its own pulleys & d[n ! wall to a numb]$ belay+-p94 ,ea* cord supports ?ree hooks & a soap-di%1 :i*1 :5 load$ ) _! own]'s prop]ty1 are haul$ up to ! ceil+ out ( ! way4 ,!re are #bjjj ( ^! cords1 spac$ #a ft4 #f ins4 ap>t1 "o to ea* man4 ,! eng9e]s & =em5 are m privileg$1 be+ provid$ ) dress+-rooms & ba?s1 p>tition$ (f f ! two ma9 halls4 ,an ext5sive clo!s wa%+ & dry+ plant has be5 laid d[n1 & also a l>ge re/aurant & cante54 ,at ,iselle1 a magaz9e hold+ #bbjj lbs4 ( dynamite is surr\nd$ & divid$ into two sep>ate p>ts by e>?-banks1 #af ft4 high4 ,! two wood5 h\ses1 9 :i* ! explosive is /or$1 are w>m$ by hot-wat] pipes to a temp]ature betwe5 #fa ,f4 & #gg ,f41 & are wat*$ by a milit>y patrol2 b at ,brigue a dynamite manufactory1 />t$ by an ent]pris+ company at ! "t ( ! comm5cem5t ( ! works1 supplies ?is commodity at frequ5t int]vals1 !reby avoid+ ! necessity ( /or+ 9 su* l>ge quantities4 ,?is dynamite factory has be5 l>gely increas$1 & supplies dynamite to ne>ly all ! m9+ & tunnel+ ent]prises 9 ,switz]l&4 ,geological ,conditions4--,be=e ! ,simplon tunnel 0 au?oriz$1 exp]t evid5ce 0 tak5 z to ! feasibility ( ! project4 ,! =eca/s ( ! ?ree eng9e]s *os51 9 ref]5ce to ! rock to be enc\nt]$ & its probable temp]ature1 h1 z f> z ! gall]ies h gone 7an aggregate di/ance ( ne>ly #b miles71 g5]ally be5 f\nd correct4 ,at ! nor? end1 a d>k argillace\s s*i/ ve9$ ) qu>tz 0 met )1 & f "t to "t b$s ( gypsum & dolomite h be5 trav]s$1 ! dip ( ! /rata be+ on ! :ole favorable to progress1 ?\gh timb]+ is resort$ to at dang]\s places4 ,wat] 0 pl5tiful at ! comm5cem5t2 9 fact1 "o inru% has n be5 /opp$1 & is /ill fl[+ d[n ! head+4 ,! total quantity ( wat] fl[+ f ! tunnel m\? is #af gallons p] second1 ( :i* #b gallons p] second are acc\nt$ = by ! drill+ ma*9es4 ,at ,iselle1 h[ev]1 a v h>d antigorio gneiss obta9s1 & is likely to ext5d = #d miles4 ,v dry & v compact1 x requires no timb]+1 & repres5ts no great difficulty to ! p[]ful ,br&t rock-drills1 :i* "w "u a head ( #cbhj ft4 ( wat]4 ,! temp]ature ( ! rock dep5ds n only on ! dep? f ! surface1 b l>gely ^u ! g5]al =m ( t surface comb9$ ) ! conductivity ( ! rock4 ,tak+ ^! po9ts into consid]ation ) ! exp]i5ce ga9$ f ! con/ruction ( ! ,/4 ,go?>d tunnel1 #ie ,f4 0 e/imat$ z ! probable maximum temp]ature1 ow+ to ! height ( ,monte ,leone 7#aa1ffj ft471 :i* lies almo/ directly ov] ! tunnel axis4 ,survey4--,aft] hav+ det]m9$ ^u ! g5]al position ( ! tunnels1 tak+ into consid]ation ! necess>y gradi5ts1 ! temp]ature ( ! rock1 & a l>ge b$ ( tr\blesome gypsum on ! nor? side1 two fix$ po9ts on ! propos$ c5t] l9e 7 tak51 "o at ea* entrance ( tunnel ,no4 #a1 & ! be>+s ( ^! two po9ts1 ) ref]5ce to a triangulation survey made 9 #ahgf1 7 calculat$ suffici5tly accurately to det]m9e1 = ! "t be+1 ! direction ( ! tunnel4 ,9 #ahih1 a new triangulation survey 0 made1 tak+ 9 elev5 summits1 ,monte ,leone hold+ ! c5tral position4 ,?is survey 0 ti$ into t ( ! ,was5horn & ,faulhorn1 made by ! ,swiss ,gov]nm5t1 & ! accuracy 0 su* t ! probable error 9 ! meet+ ( ! two head+s is only #f cms4 or #b ins4 ,on ! top ( ea* summit is plac$ a signal1 consi/+ ( a small pill> ( masonry f\nd$ on rock1 & capp$ ) a %>p po9t$ cone ( z9c1 #a ft4 #f ins4 high4 ,an obs]vatory 0 built at ea* end ( ! tunnel 9 su* a position t ?ree ( ! summits c\ld be se51 a condition v difficult to fulfill on ! s\? side ow+ to ! dep? ( ! gorge1 ! m\nta9s on ei!r side be+ ov] #gjjj ft4 high4 ,hav+ tak5 ! angles to & f ea* visible signal1 & !refrom hav+ calculat$ ! direction ( ! tunnel1 x 0 necess>y to fix1 ) extreme accuracy1 sight+-po9ts on ! axis ( ! tunnel1 9 ord] to avoid sight+ on to ! surr\nd+ peaks = ea* subsequ5t correction ( ! al9em5t ( ! gall]ies4 ,to d ?is1 a !odolite #bd ins4 long & #b ins4 9 diamet]1 ) a magnify+ p[] ( #dj times1 0 set up 9 ! obs]vatory1 & ab\t #ajj read+s 7 tak5 ( ! angles betwe5 ! surr\nd+ signals & ! requir$ sight+-po9ts4 ,9 ?is mann] ! error likely to occur 0 dim9i%$ to less ?an #a4 ,?us at ! nor? end two po9ts 7 f\nd ab\t #eej yds4 be=e & beh9d ! obs]vatory1 :ile on ! s\? side1 ow+ to ! n>r[ness ( ! gorge1 ! po9ts c\ld only be plac$ at #hb yds4 & #abf yds4 9 front4 ,"o ( ^! sight+-po9ts consi/s ( a f9e scrat* rul$ on a piece ( glass fix$ 9 an iron frame1 beh9d :i* is plac$ an acetyl5e lamp1--corrections ( al9em5t are always done by night1--! :ole be+ rigidly fix$ into a ni*e cut 9 ! rock & protect$ f climatic & o!r di/urb+ ag5cies by an iron plate4 ,me?od ( ,*eck+ ,al9em5t4--,! direction ( head+ ,no4 #a is *eck$ by exp]ts f ! ,gov]nm5t ,survey ,dep>tm5t at ,lausanne ab\t ?ree times a ye>1 & = ?is purpose a transit in/rum5t is set up 9 ! obs]vatory4 ,a numb] ( ?ree-legg$ iron tables are plac$ at int]vals ( #a mile or #b miles along ! axis ( tunnel ,no4 #a1 & ^u ea* ( ^! is plac$ a horizontal plane1 movable by means ( an adju/+ screw1 9 a direction at "r angles to ! axis1 along a graduat$ scale4 ,on ?is plane are small sockets1 into :i* ! legs ( an acetyl5e lamp & scre51 or ( ! transit in/rum5t1 c be quickly & accurately plac$4 ,! scre5 has a v]tical slit1 #c ins4 9 height1 & v>iable betwe5 94 & 94 9 bread?1 accord+ to ! /ate ( ! atmosph]e1 & at a di/ance %[s a f9e ?read ( light4 ,! in/rum5t1 hav+ fir/ be5 sight$ on to ! illum9at$ scrat* ( ! sight+-po9t1 is direct$ up ! tunnel1 :]e a ?read ( light is %[n f ! fir/ table4 ,) ! aid ( a telephone ?is light is adju/$ s t its image is exactly co9cid5t ) ! cross hairs1 & ! read+ on ! graduat$ scale is not$4 ,?is is done f\r or five times1 ! av]age ( ^! read+s be+ tak5 z correct1 & ! plane is clamp$ to t av]age4 ,! in/rum5t is !n tak5 to ! fir/ table & is plac$ quickly & accurately ov] ! po9t j f\nd 7by means ( ! sockets71 & ! lamp is c>ri$ to ! obs]vatory4 ,aft] fir/ sight+ back1 a second po9t is giv5 on ! second table1 & s on4 ,^! po9ts are m>k$ ei!r tempor>ily 9 ! ro( ( ! head+ by a %ort piece ( cord hang+ d[n1 or p]man5tly by a brass po9t held by a small /eel cyl9d]1 #h ins4 long & #c ins4 9 diamet]1 emb$d$ 9 concrete 9 ! rock floor1 & protect$ by a circul> ca/+1 also sunk 9 cem5t concrete1 hold+ an iron cov] resembl+ t ( a small manhole4 ,f "t to "t ! al9em5t is *eck$ f ^! po9ts by ! eng9e]s1 & aft] ea* bla/ ! g5]al direction is giv5 by ! h& f ! tempor>y po9ts4 ,to *eck ! results ( ! triangulation survey1 a/ronomical obs]vations h be5 tak5 simultane\sly at ea* end4 ,) reg>d to ! levels1 ^? giv5 on ! excell5t ,gov]nm5t surveys h be5 tak5 z correct1 b !y h also be5 *eck$ ov] ! pass4 ,details ( ,tunnels4--,9 cross-section1 tunnel ,no4 #a is #ac ft4 #g ins4 wide at =mation level1 increas+ to #af ft4 #e ins41 ) a total height ( #ah ft4 above rail-level1 & a cross-sectional area ( ab\t #bej sq4 ft4 ,?is l>ge section w all[ ( small repairs be+ execut$ 9 ! ro( )\t int]ruption ( ! traffic1 & w also all[ ( /r5g!n+ ! walls by additional masonry on ! inside4 ,! ?ickness ( ! l9+1 nev] :olly abs5t1 & ! mat]ial ( :i* x is compos$1 dep5d ^u ! pressure to be resi/$1 & only 9 ! wor/ case is an inv]t resort$ to4 ,! side dra91 to :i* ! rock floor is made to slope1 w be compos$ ( half-pipes ( #g to #a cem5t concrete4 ,! ro( is con/ruct$ ( radial /ones4 ,tunnel ,no4 #b1 be+ left z a head+1 is driv5 on t side ne>e/ to ,no4 #a1 to m9imize ! l5g? ( ! cross-head+s1 & measures #aj ft4 #b ins4 wide by #f ft4 #g ins4 high4 ,masonry is us$ only :]e necess>y1 & 9 t case is s built z to =m "p ( ! l9+ ( ! tunnel :5 ev5tually complet$4 ,concrete is put 9 to =m a f\ndation = ! side wall1 & a wat] *annel4 ,! cross-head+s1 connect+ ! two p>allel head+s1 occur e #bbj yds41 & are plac$ at an angle ( #ef to ! axis ( ! tunnel1 to avoid %>p curves 9 ! contractors' railway l9es4 ,!y w ev5tually be us$ z mu* z possible = refuges1 *amb]s = /or+ ! tools & equipm5t ( ! platelay]s1 & signal-cab9s4 ,! refuges1 #f ft4 #g ins4 wide by #f ft4 #g ins4 high & #c ft4 #c ins4 deep1 occur e #aaj y>ds1 e t5? be+ enl>g$ to #i ft4 #aj ins4 wide by #i ft4 #aj ins4 deep & #aj ft4 #b ins4 high1 /ill l>g] *amb]s be+ con/ruct$ at great] int]vals4 ,me?od ( ,excavation4--,! "w at ea* end ( ! tunnel is c>ri$ on q indep5d5tly1 consequ5tly1 ?\gh simil> 9 pr9ciple1 ! me?ods v>y 9 detail1 ap>t f ! fact t diff]5t geological /rata require diff]5t treatm5t4 ,broadly speak+1 ! two p>allel head+s1 ea* #ei sq4 ft4 9 section1 are fir/ driv5 by means ( drill+-ma*9es & ! use ( dynamite1 ?is "w be+ c>ri$ on day & night1 sev5 days 9 ! week2 ,no4 #a head+ is !n enl>g$ to full size by h&-drill+ & dynamite4 ,on ! ,italian side1 :]e ! rock is h>d & compact1 breakups are made at int]vals ( #ej yds41 & a top gall]y is driv5 9 bo? directions1 b1 = v5tilation reasons1 is nev] all[$ to get m ?an #d yds4 ahead ( ! break-up1 :i* is gradually l5g!n$ & wid5$ to ! requir$ section4 ,no timb]+ is requir$1 except to facilitate ! excavation & ! con/ruction ( ! side walls4 ,/eel c5t]s are employ$ = ! ar*2 !y entail few] supports1 give m room1 & are capable ( be+ us$ ov] aga9 m frequ5tly )\t damage4 ,!y consi/ ( two ,i-beams b5t to a template & rivet$ toge!r at ! cr[n1 re/+ at ei!r side on scaffold+ at int]vals ( #f ft42 longitud9als #ab ft4 by #d ins4 by #d ins4 support ! ro(4 ,h& rock-drill+ is c>ri$ out 9 ! ord9>y way1 "o man hold+ ! tool & a second /rik+2 measurem5ts ( excavation are tak5 e #b or #c yds41 a plumb-l9e is susp5d$ f ! c5t] ( ! ro(1 & at e half-met] 7#bj ins47 ( height horizontal measurem5ts are tak5 to ea* side4 ,at ! ,brigue end a s(t] rock is enc\nt]$1 necessitat+ at times heavy timb]+ 9 ! head+1 & especially 9 ! f9al excavation to full size1 ,fig4 #ef4 ,! bottom head+1 #f ft4 #f 94 high1 is driv5 9 ! c5t]1 & ! head+ is !n wid5$ to ! full ext5t & timb]$2 ! concrete =m+ ! wat] *annel & ! f\ndation = "o side wall is put 92 ! side walls are built to a height ( #f ft4 #f ins41 & ! tunnel is fully excavat$ to a fur!r height ( #f ft4 #f ins4 f ! fir/ /ag+4 ,! side walls are !n cont9u$ up = ! second #f ft4 #f ins41 & f ! second floor a ?ird height ( #f ft4 #f ins4 is excavat$ & timb]$4 ,f9ally ! cr[n is cle>$ out1 heavy wood5 c5t]s are put 91 ! ar* is turn$ & all timb]s are )drawn except ! top pol+-bo>ds1 support+ ! loose rock4 ,illu/ration3 ,,fig4 #ef4--,sket*es ,%[+ ,sequ5ce ( ,"w 9 ,excavat+ & ,l9+ ! ,simplon ,tunnel4 #a #b #c #d #e #f #g #h ,! masonry = ! side walls is obta9$ ei!r f ! tunnel itself or f a neighbor+ qu>ry1 & v>ies 9 "* accord+ to ! pressure2 b ! face ( ! ar* is always ( cut or artificial /ones1 ! latt] be+ #g to #a cem5t concrete4 ,:]e ! al9em5t head+1 or ! 8gall]y ( direction10 jo9s ! curv+ portion ( tunnel ,no4 #a1 ! section is v mu* great]1 & necessitates special timb]+4 ,transport 7,italian ,side74--,a small l9e ( railway1 #b ft4 #g ins4 gauge1 ) #dj-lb4 rails1 ent]s all ?ree portals2 b s9ce ! con/ruction ( a wood5 bridge ov] ! ,div]ia1 ! r\te ?r\gh ! 8gall]y ( direction10 across head+ ,no4 #b1 to tunnel ,no4 #a1 is us$ exclusively2 ?is railway leads to ! face 9 bo? head+s1 &1 :]e conv5i5t1 f "o head+ to ! o!r by ! cross-gall]ies4 ,diff]5t types ( wagons are 9 use2 b 9 g5]al !y are f\r-:eel$1 non-tipp+ box wagons1 suppli$ ) brakes & hold+ #b cu4 yds4 ( dbris4 ,a special type ( locomotive is us$1 design$ to pass r\nd curves ( #ej ft4 radius1 & suppli$ ) a specially l>ge boil] to avoid fir+ 9 ! tunnel4 ,illu/ration3 ,,fig4 #eg4--;,g5]al ,details ( ! ,br&t ,rot>y ,drills ,employ$ at ! ,simplon ,tunnel4 ,me?od ( ,work+4--,! drill+-ma*9es employ$ are ( ! ,br&t type1 ,fig4 #eg1 & are m\nt$ 9 ! foll[+ mann]3 ,a small f\r-:eel$ c>riage supports at its c5t] a beam1 ! %ort] arm ( :i* c>ries ! bor+ me*anism & ! long] a c\nt]poise2 ne> its c5t] is ! di/ributor4 ,9 ! %ort arm is a clamp hold+ ! rack-b> or butt+ column1 :i* is a wr\ght-iron cyl9d] ) a plung] con/itut+ a ram1 & is jamm$ by hydraulic pressure betwe5 ! walls ( ! head+1 ?us =m+ a rigid support = ! bor+-ma*9e1 & an effici5t abutm5t aga9/ ! reaction ( ! drill4 ,?is rack-b> c be rotat$ on its clamp 9 a plane p>allel to ! axis ( ! beam4 ,?ree or f\r sep>ate bor+-ma*9es c be m\nt$ on ! rack-b>1 & c be adju/$ 9 any reasonable position4 ,! bor+-ma*9e p]=ms ! d\ble function ( cont9ually press+ ! drill into ! rock by means ( a holl[ ram 7,i7 & ( imp>t+ to ! drill & ram a uni=m rot>y motion4 ,?is rot>y motion is giv5 by a tw9 cyl9d] s+le-act+ hydraulic motor 7,e71 ! two pi/ons1 ( #b ins4 /roke1 act+ reciprocally z valves4 ,! cranks are fix$ at an angle ( #ij to ea* o!r on ! %aft1 :i* c>ries a worm1 ge>+ ) a worm-:eel 7,q7 m\nt$ ^u ! %ell 7,r7 ( ! holl[ ram 7,i71 & ?is %ell 9 turn engages ! ram by a long fea!r1 leav+ x free to slide axially to or f ! face ( ! rock4 ,! av]age spe$ ( ! motor is #aej revolutions to #bjj revolutions p] m9ute1 ! maximum spe$ be+ #cjj revolutions p] m9ute4 ,! loss ( p[] betwe5 ! worm & worm-:eel is only #ae at ! mo/2 ! worm be+ ( h>d5$ /eel & ! :eel ( gun-metal1 ! two surfaces 9 contact acquire a high degree ( poli%1 result+ 9 little we>+ or heat+4 ,tak+ into consid]ation all o!r s\rces ( loss1 #gj ( ! total p[] is utiliz$4 ,! pressure on ! drill is ex]t$ by a cyl9d] & holl[ ram 7,i71 :i* revolves ab\t ! diff]5tial pi/on 7,s71 :i* is fix$ to ! envelope hold+ ! %ell 7,r74 ,?is envelope is rigidly connect$ to ! b$-plate ( ! motor1 &1 by means ( ! v]tical h+e & p9 7,t71 is held by ! clamp 7,v7 embrac+ ! rack-b>4 ,:5 wat] is admitt$ to ! space 9 front ( ! diff]5tial pi/on ! ram c>ry+ ! drill+-tool is ?ru/ =w>d1 & :5 admitt$ to ! annul> space beh9d ! pi/on1 ! ram rec$es1 )draw+ ! tool f ! bla/-hole4 ,! drill prop] is a holl[ tube ( t\gh /eel #b ins4 9 ext]nal diamet]1 arm$ ) ?ree or f\r %>p & h>d5$ tee?1 & makes f five to t5 revolutions p] m9ute1 accord+ to ! nature ( ! rock4 ,:5 ! ram has rea*$ ! end ( its /roke ( #b ft4 #b ins41 ! tool is quickly )drawn f ! hole & unscrew$ f ! ram2 an ext5sion rod is !n screw$ into ! tool & into ! ram1 & ! bor+ is cont9u$1 additional l5g?s be+ add$ z ! tool gr9ds =w>d2 ea* *ange ( tool or rod takes ab\t #ae secs4 to #be secs4 to p]=m4 ,! ext5sion rods are =g$ /eel tubes1 fitt$ ) f\r-?read$ screws1 & hav+ ! same ext]nal diamet] z ! drill4 ,!y are made 9 /&>d l5g?s ( #b ft4 #h ins41 #a ft4 #aj ins41 & #aa ins4 ,! total weight ( ! drill+-ma*9e is #bfd lbs41 & t ( ! rack-b> :5 full ( wat] is #cjh lbs4 ,! exhau/ wat] f ! two motor cyl9d]s escapes ?r\gh a tube 9 ! c5t] ( ! ram & along ! bore ( ! ext5sion rods & drill1 !reby sc\r+ away ! dbris & keep+ ! drill cool2 any sup]flu\s wat] f9ds an exit ?r\gh a hose bel[ ! motors & !nce away d[n ! head+4 ,! di/ributor1 already m5tion$1 supplies ea* bor+-ma*9e & ! rack-b> ) hydraulic pressure f ! ma9s1 ) :i* connection is effect$ by means ( flexible or articulat$ pipe connections1 all[+ fre$om 9 all directions4 ,! area ( ! pi/on = advanc+ ! tool is #ae sq4 ins41 :i*1 "u a pressure ( #adgj lbs4 p] sq4 941 gives a pressure ( ov] #aj tons on ! tool1 :ile = )draw+ ! tool #b tons is available4 ,9 ! rock f\nd at ,iselle1 namely1 antigorio gneiss1 a hole #b ins4 9 diamet] & #c ft4 #c ins4 9 l5g? is drill$1 normally1 9 #ab m9s4 to #be m9s42 a daily rate ( advance ( #ah ft4 to #ai ft4 #f ins4 is made 9 a head+ hav+ a m9imum cross-section ( #ei sq4 ft42 ! "t tak5 to drill t5 to twelve holes1 #d ft4 #g ins4 deep1 is #b hrs4 ,:5 ! dbris result+ f "o op]ation has be5 suffici5tly cle>$ away1 a /eel floor+1 :i* is provid$ ne> ! face to enable %ovel+ to be m easily done1 & to give an ev5 floor = ! :eels ( ! drill+-c>riage1 is laid b>e at ! head ( ! l9e ( rails1 & ! drill+-ma*9es are br\ght up on _! c>riage by eight or t5 m54 ,:5 advanc$ suffici5tly close to ! face1 ! rack-b> is slew$ r\nd across ! gall]y & is w$g$ up aga9/ ! rock sides2 connection is made betwe5 ! di/ributor & ! hydraulic ma91 by means ( ! flexible pipe1 & pressure is suppli$ by a small copp] tube to ! rack-b> ram1 !reby rigidly hold+ ! ma*9e4 ,next1 connections are made betwe5 ! ?ree drill+-ma*9es & ! di/ributor1 & 9 #bj m9s4 f ! "t ! ma*9e 0 br\ght up all ?ree drills are h>d at "w1 wat] p\r+ f ! holes4 ,! noise ( ! motors & gr9d+-tools is suffici5t to dr[n all b %\ts2 & :]e ! ext5sion rods d n fit tightly1 small jets ( wat] play 9 all directions1 necessitat+ ! we>+ ( t>paul9s by ! m5 direct+ ! tools4 ,light+ is done :olly by small oil-lamps1 provid$ ) a hook to facilitate fix+ 9 any crack 9 ! rock2 electricity w probably be us$ to light t portion ( ! tunnel :i* is complet$4 ,two m5 are allott$ to ea* drill1 "o to drive ! motor1 ! o!r to direct & repl5i% ! tool1 "o =eman & two m5 9 res]ve complet+ ! gang4 ,a small hamm] is freely us$ to loos5 ! screw jo9ts ( ! ext5sion rods & drill4 ,a hole is usually comm5c$ by a two-edg$ flat-po9t$ tool1 until a suffici5t dep? is rea*$ to prev5t ! circul> tool f w&]+ ov] ! face ( ! rock1 b 9 _m in/ances ! hole is comm5c$ ) a circul> tool4 ,! exhau/ wat] dur+ ?is p]iod fl[s away by ! hose und]nea? ! motor4 ,9 ! antigorio gneiss1 t5 to twelve holes are drill$ = ea* attack1 ?ree to f\r 9 ! c5t] to a dep? ( #c ft4 #c ins41 ! rema9d]1 dispos$ r\nd ! outside ( ! face1 hav+ a dep? ( #d ft4 #g ins4 ,! av]age "t tak5 to complete ! holes is #a hr4 to #b hrs4 ,in/ead ( pulv]iz+ ! rock1 z d ! diamond drills1 x is f\nd t ! rock is cru%$1 & t headway is ga9$ some:at 9 ! mann] ( a circul> saw ?r\gh wood4 ,! core ( rock inside ! tool breaks up into small pieces1 & c be tak5 out if necess>y :5 ! drill requires l5g!n+4 ,! l[e/ holes1 incl9$ d[nw>ds1 are full ( wat]2 consequ5tly two detonators & two fuses are ins]t$1 b ap>t f ?is1 wat] has little effect on ! *>ge4 ,! fuses ( ! c5tral holes are br\ght toge!r & cut (f %ort] ?an ^? ( ! out] holes1 9 ord] t !y may explode fir/ to increase ! effect ( ! out] *>ges4 ,all portable objects1 su* z drills1 pipe connections1 tools1 etc41 h mean:ile be5 c>ri$ back2 ! /eel floor+ is cov]$ ov] ) a lay] ( dbris to prev5t injury f fall+ rock1 & to ! end ( ! hydraulic ma9 is screw$ a brass plug pi]c$ by five holes2 & imm$iately ! explosions occur a valve is op5$ 9 ! tunnel1 & five jets ( wat] play ^u ! rock1 lay+ ! du/ & cle>+ ! air4 ,! necessity = ?is 0 %[n on "o occasion :5 ?is nozzle 0 brok5 by ! explosion & ! wat] _h to be turn$ (f imm$iately to avoid useless wa/e2 on rea*+ ! face1 ! atmosph]e 0 f\nd to be s highly *>g$ ) du/ & smoke t x 0 impossible to di/+ui% ! /ones at ! feet1 al?\gh a lamp _h be5 plac$ on ! gr\nd2 & despite ! fact t ! air tube 0 9 full bla/1 ! m5 exp]i5c$ great difficulty 9 brea?+4 ,a truck is n[ br\ght up1 & f\r m5 cle> a passage 9 front1 ?r\gh ! heap ( dbris1 two ) picks & two ) %ovels1 :ile on ei!r side & beh9d are z _m m5 z space w p]mit4 ,! /one is ?r[n ei!r to ! sides ( ! head+ or into ! wagon1 %ovel+ be+ greatly aid$ by ! /eel floor+1 :i*1 be=e ! explosion1 _h be5 laid ov] ! rails = ne>ly #aj yds4 d[n ! tunnel to receive ! fall+ rock4 ,^! /eel plates are tak5 up :5 cle>$1 & ! wagon is pu%$ =w>d until ! drill+-ma*9e c be br\ght up aga91 leav+ ! rema9+ dbris at ! sides to be h&l$ at leisure dur+ ! next attack4 ,! ro( & side walls are1 ( c\rse1 c>efully exam9$ ) ! pick1 to discov] & deta* any loose or hang+ rock4 ,! times tak5 = ea* portion ( ! attack 9 ?is p>ticul> antigorio gneiss are z foll[s3 ,br++ up & adju/m5t ( drills1 #bj m9s42 drill+1 betwe5 #a hr4 & #b hrs42 *>g+ & fir+1 #ae m9s42 cle>+ away dbris1 #b hrs42 or = "o :ole attack1 betwe5 #d hrs4 & #e hrs41 result+ 9 an advance ( #c ft4 #i 941 or a daily advance ( ne>ly #ah ft4 ,f ?is x appe>s t ! "t sp5t 9 cle>+ away ! dbris equals t tak5 up 9 drill+1 & x is 9 ?is cle>+ t a sav+ ( "t is likely to be effect$ r ?an 9 ! process ( drill+4 ,_m s*emes h be5 tri$1 su* z a me*anical pl[ = mak+ a passage2 at ,brigue1 8m>9age10 or cle>+ by means ( p[]ful high-pressure wat]-jets1 direct$ d[n ! tunnel1 0 tri$1 b ! idea is n yet suffici5tly develop$4 ,ano!r s]ies ( exp]im5ts has be5 tri$ at ,brigue ) reg>d to ! utilization ( liquid air z an explosive ag5t in/ead ( dynamite2 & = ?is purpose a plant has be5 laid d[n1 consi/+ ( "o ammonia-compressor1 two air-compressors1 & two refrig]ators1 furni%+ gallon ( liquid air p] h\r at an exp5diture ( #ag ,h4 ,p4 ,! sy/em us$ is t ( ,pr(essor ,l9de1 :o himself directs ! exp]im5ts4 ,! great difficulty exp]i5c$ is t ( %ort5+ ! int]val ( "t t mu/ elapse betwe5 ! manufacture ( ! c>tridge & its explosion4 ,! liquid oxyg51 ) :i* ! c>tridge1 conta9+ kieselguhr 7silici\s e>?7 & p>aff91 is saturat$1 evaporates v readily1 los+ p[] e mom5t2 h5ce ! effect ( ea* c>tridge _c be gu>ante$1 & ?\gh x is an exce$+ly p[]ful explosive :5 us$ imm$iately aft] manufacture1 no practical result has yet be5 obta9$4 ,p[] ,/ation4--,wat] is abundant at ei!r end1 & !re=e hydraulic p[] is ! motive =ce employ$4 ,on ! ,italian side1 a dam #e ft4 high has be5 ?r[n across ! ,div]ia at a po9t ne> ! ,swiss fronti]1 ab\t #c miles above ! site ( ! in/allations4 ,a portion ( ! wat] ?us held back ent]s1 ?r\gh regulat+ doors & grat+s1 a masonry *annel lead+ to two p>allel settl+ tanks1 ea* #aaa ft4 by #af ft41 :5ce1 aft] dropp+ all its s& & solid matt]1 ! n[ pure wat] passes into ! wat]-h\se1 &1 aft] fl[+ ov] a dam1 ?r\gh a grat+ & pa/ ! admission doors1 ent]s a metallic conduit ( #c-;ft4 pipes4 ,ea* ( ! settl+ tanks & ! approa* canal are provid$ ) doors at ! l[] end lead+ direct to ! riv]1 ?r\gh :i* all ! s& & solid matt] deposit$ c be sc\r$ naturally by all[+ ! riv]-wat] to ru% freely ?r\gh4 ,= ?is purpose ! floor ( ! bas9s is on an av]age gradi5t ( #a 9 #cj4 ,= a simil> reason ! riv]-b$ j outside ! entrance to ! approa* canal is l9$ ) wood5 planks1 f :i* ! /ones collect+ beh9d ! dam c be sc\r$ by all[+ an iron flap1 h+$ at ! bottom1 to *ange its position f ! v]tical to ! horizontal 9 a gap left purposely 9 ! dam1 s caus+ a ru%+ torr5t to sweep x clean4 ,! *ief levels are3 ,level ( wat] at dam #gid4jj met]s above sea level4 9 wat]-h\se #gic4gj at turb9es #fah4ej giv+ a total fall ( #age4bj ms4 or #egj ft41 & a pressure ( #ag4eb atmosph]es4 ,! quantity ( wat] capable ( be+ tak5 f ! ,div]ia 9 w9t]1 :5 ! riv]s :i* are dep5d5t ^u ! m\nta9 sn[s = _! supply are at _! l[e/1 is calculat$ to be #ceb gallons p] second4 ,?us1 tak+ ! fall to be dim9i%$ by friction1 etc41 to #ddj ft41 & ! useful effect at #gj1 !re is obta9$ #bjjj ,h4 ,p4 on ! turb9e %aft4 ,! metallic conduit v>ies 9 mat]ial accord+ to ! pressure2 ?us ca/-iron pipes #c ft4 9 diamet] & 94 ?ick are us$ up to a pressure ( #b atmosph]es1 f :i* po9t !y are ( wr\ght-iron4 ,! ca/-iron portion has ( late caus$ a good deal ( tr\ble1 ow+ to settlem5t ( ! pi]s caus+ occasional bur/s1 consequ5tly a masonry pi] has be5 plac$ "u ea* jo9t ( ?is portion4 ,! foll[+ table gives ! ?icknesses & diamet]s1 v>y+ ) ! pressure3 ---------------------------------------- - ,,wat] ,,?ickness4 ,,diamet]4 ,,weight ,,pressure4 ,,p] ,,y>d4 --------------------------------------- ,head ,milli-,in*4,feet4,in*es4 ,lbs4 9 ,feet4met]s4 --------------------------------------- #bdf #f #c #j #cbf #caa #g 444 #c #j #chc #cfj #h 444 #c #j #dca #cic #i 444 #c #j #dhc #dbf #aj 444 #c #j #eef #dgf #ab 444 #c #j #fea #eij #af #c #c #igg --------------------------------------- ,?is pipe is support$ e #cj ft4 on small masonry pi]s1 on ! top ( :i* is plac$ a block ( wood holl[$ out to receive ! pipe1 ?us all[+ any movem5t due to ! contraction & expansion ( ! conduit4 ,h[ev]1 to prev5t ?is movem5t becom+ excessive1 ! pipe is pass$ at int]vals ( #cjj yds4 to #ejj yds4 ?r\gh a cubical block ( masonry ( #ac ft4 side1 /r5g!n$ by longitud9al tie-b>s4 ,five b&s ( angle-b> rivet$ r\nd ! pipe1 ) _! flanges emb$d$ 9 ! masonry1 con/itute a rigid fix$ po9t4 ,/raw mats are ?r[n ov] ! pipe :]e x is expos$ to ! sun4 ,! temp]ature ( ! conduit is n1 h[ev]1 f\nd to v>y greatly1 s9ce ! pipe is kept full ( wat]4 ,to supply ! rock-drills ) wat] at a maximum pressure ( #ajj atmosph]es1 or #adgj lbs4 p] sq4 941 a plant ( f\r pairs ( high-pressure pumps has be5 laid d[n1 & a /ill l>g] addition is 9 c\rse ( erection4 ,at pres5t1 two ,pelton turb9es ( #bej ,h4,p4 ea*1 runn+ at #agj revolutions p] m9ute1 drive ! pumps1 by means ( too!d ge>+1 at #fc revolutions p] m9ute4 ,^! pumps are ( v simple b /rong con/ruction1 s+le suction & d\ble deliv]y1 entail+ "o suction & "o deliv]y-valve1 bo? heavy & bo? ( small lift4 ,! l>g] portion ( ! plung] has exactly d\ble ! cross-sectional area ( ! small] portion1 s t 9 ! =w>d /roke half ( ! wat] tak5 9 at ! la/ admission is pump$ into ! high-pressure ma9s1 & at ! same "t a fre% supply ( wat] is suck$ 94 ,dur+ ! backw>d /roke half ( ?is new supply is pump$ into ! ma9s1 & ! rema9d] ent]s ! second *amb]1 to be pump$ dur+ ! next =w>d /roke4 ,?us ! "w done 9 ! two /rokes is practically ! same4 ,! pumps are 9 pairs1 & are set at an angle ( #ij1 to insure uni=m pressure & uni=m deliv]y 9 ! ma9s4 ,_! size v>ies2 b at ,iselle !re are ?ree pairs1 ) a /roke ( #b ft4 #b ins41 & ! plung]s ( #b 94 & #a ins4 7approximately7 9 diamet]1 supply+ #a4cb gallons p] second4 ,to avoid injury to ! valves1 ! wat] to be pump$ is tak5 f a /ream up ! m\nta9 side1 & is pass$ ?r\gh filt] scre5s4 ,! high-pressure wat]1 aft] pass+ an accumulator1 ent]s ! tunnel 9 solid drawn wr\ght-iron tubes1 #c ins4 9 int]nal diamet]1 94 ?ick1 & 9 l5g?s ( #bf ft4 ,! diamet] ( ^! ma9s v>ies ) _! l5g?1 s z to avoid loss ( pressure4 ,) ! #abej yds4 ( tunnel n[ driv5 #aj atmosph]es are lo/4 ,at ,brigue ! in/allations are1 z f> z possible1 id5tical4 ,! ,rhone wat]1 h[ev]1 be=e rea*+ ! wat]-h\se1 is c>ri$ f ! filt] bas9s1 a di/ance ( #b miles1 9 an armor$ canal built ^u ! ,h5nebique sy/em1#i ! walls & support+ beams1 ( cem5t concrete1 be+ /r5g!n$ by int]nal tie-b>s ( /eel4 ,! concrete /ruts1 resembl+ balks ( timb] at a di/ance1 are occasionally #ce ft4 high & #a ft4 #g ins4 squ>e4 ,! metallic conduit is #e ft4 9 diamet]1 ) a m9imum fl[ ( #agf cu4 ft4 p] second & a total fall ( #ahe ft4 ,9 case wat]-p[] %\ld be unavailable1 ?ree semi-portable /eam eng9es1 two ( #hj ,h4,p4 & "o ( #fj ,h4,p41 are always kept 9 read9ess at ea* end ( ! tunnel1 & are ge>$ by belts to ! turb9e %aft4 #i ,network ( /eel rods emb$d$ 9 concrete4 ,v5tilation4--,9 tunnel+1 "o ( ! mo/ important problems to be solv$ is t ( v5tilation1 & x is = ?is reason t ! ,simplon tunnel consi/s ( two p>allel head+s ) cross cuts at int]vals ( #bbj yds4 ,at ,brigue1 a %aft #afd ft4 deep 0 sunk ?r\gh ! ov]ly+ rock until ! 8gall]y ( direction0 0 enc\nt]$4 ,up ?is *imney ! f\l air is drawn by wood fires1 ! fre% air--a volume ( #ai1jjj1jjj cu4 ft4 p] day1 or #ac1bjj cu4 ft4 p] m9ute--ent]+ by head+ ,no4 #b1 p5etrat+ up to ! la/ cross gall]y1 & return+ by tunnel ,no4 #a4 ,! entrances ( ,no4 #a & ! 8gall]y ( direction10 besides ^? ( all ! int]m$iate cross gall]ies1 are clos$ by doors4 ,by ?is arrangem5t1 h[ev]1 fre% air does n rea* ! work+ faces2 !re=e a pipe1 #h ins4 9 diamet]1 is l$ f ! fre% air 9 ,no4 #b to )9 #ae yds4 ( ! face ( ea* head+1 & up ?is pipe a draft ( air is induc$ by means ( a jet ( wat]1 ! volume to ea* face be+ #hjj cu4 ft4 p] m9ute4 ,"o s+le jet ( wat] f ! high-pressure ma9s1 ) a diamet] ( 941 is capable ( supply+ ov] #ajjj cu4 ft4 ( air p] m9ute at ! end ( #afj yds4 ( pipe1 & dur+ ! attack ! m5 at ! drills are 9 a con/ant breeze ) ! !rmomet] /&+ at #gj ,f4 ,at ,iselle1 air is bl[n into ! entrance ( head+ ,no4 #b at ! rate ( #ad1ajj cu4 ft4 p] m9ute by two fans driv5 f ! turb9e %aft4 ,?is air travels f ! fans along a pipe #ah ins4 9 diamet]1 till a po9t #ae yds4 up ! tunnel is rea*$1 :]e beyond a door ! pipe n>r[s to =m a nozzle #aj ins4 9 diamet]4 ,?is door is kept op5 to all[ ! outside air to be induc$ up ! tunnel1 z ! head+s are at pres5t only #bejj yds4 long1 giv+ a resi/ance ( n q suffici5t p[] to cause ! air to return4 ,! fre% air !n travels up ,no4 #b1 cross+ ov] ! top ( ! 8gall]y ( direction10 f :i* x is %ut (f by doors1 to ! la/ cross gall]y1 return+ by ,no4 #a1 & f9ally leav+ ei!r by ! 8gall]y ( direction0 or by ,no4 #a4 ,a sy/em ( cool+ ! air & driv+ x on by means ( a l>ge numb] ( wat]-jets w be in/all$ 9 ,no4 #b :]e t head+ crosses ov] ! 8gall]y ( direction10 b at pres5t !re is no ne$ = x4 ,! av]age temp]ature at ! face is #gc ,f4 dur+ ! drill+ op]ation1 #gf ,f4 aft] fir+ ! *>ges1 & a maximum ( #hj ,f41 lately atta9+ to #hf ,f4 on ! s\? side1 ) #hj ,f4 & #he ,f4 be=e & aft] fir+4 ,! temp]ature ( ! rock is tak5 at e #aaj yds4 9 holes #e ft4 deep1 & %[s a gradual increase accord+ to ! dep? ( ov]-lay+ rock1 to ! conductivity ( ! rock1 & to ! =m ( ! m\nta9 surface4 ,! maximum hi!rto rea*$ on ! nor? side is #fh ,f41 :ile on ! s\? side1 al?\gh a small] di/ance has be5 trav]s$1 x atta9s to #gi ,f41 due to ! m rapid increase 9 dep?4 ,moreov]1 ! temp]ature ( ! rock is obs]v$ at ! p]man5t /ations1 #eej yds4 f ! entrances1 9 its relation to t ( ! tunnel & outside air1 & ?\gh on ! nor? side t ( ! rock v>ies almo/ z quickly z t ( ! tunnel air1 on ! s\? x is influ5c$ v mu* less4 ,a few /ati/ics may be ( int]e/ ) reg>d to ! progress ( ! la/ ?ree mon?s 7tak5 f ! trime/rial report ( ,janu>y1 #aijj74 ,at ,brigue1 :]e !re are ?ree drill+-ma*9es 9 ,no4 #a & two 9 ! p>allel head+1 ! total l5g? excavat$ 0 #iie yds4 or #fdji cu4 yds4 9 #hi work+ days1 ! av]age cross-sectional area be+ #eg sq4 ft4 ,?is requir$ #ejg attacks & #cjff holes1 :i* _h a total dep? ( #bf1fjj ft4 & #ad1gjj re-%>p5+s ( ! drill+-tool1 ) #dd1jjj lbs4 ( dynamite4 ,! av]age "t occupi$ 9 drill+ 0 #b hrs4 #de m9s41 :ile *>g+1 fir+1 & cle>+ away ! dbris took #f hrs41 #ce m9s4 ,at ,brigue #fdh m5 & #bi horses 7 employ$ at "o "t 9 ! tunnel4 ,at ,iselle ! numb]s 7 #dif m5 & #af horses1 work+ 9 %ifts ( #h hrs4 ,outside ! tunnel1 9 ! %ops1 =ges1 etc41 ! m5 "w #h hrs4 to #aa hrs4 p] day1 ! total be+ #eda m5 at ,brigue & #cdf m5 at ,iselle4 ,on ! ,italian side1 :]e ! rock is v mu* h>d]1 !re 7 ?ree drill+-ma*9es 9 ea* head+2 ! total l5g? excavat$1 ) a cross-sectional area ( #fb sq4 ft41 0 #ifj yds4 or #fgjj cu4 yds4 9 #ia work+ days4 ,?is requir$ #fa1bic re-%>p5$ tools1 #geh attacks1 #gidj holes ) a total dep? ( #cc1jjj ft41 & #ef1jjj lbs4 ( dynamite4 ,! av]age "t sp5t 9 drill+ 0 #b hrs4 #ee m9s41 & 9 *>g+ & cle>+ #b hrs4 #cf m9s4 ,?us1 9 ! h>d gneiss1 to excavate #a cu4 yd4 ( rock requir$ #h lbs4 ( dynamite1 & ea* tool pi]c$ #f ins4 ( rock be=e x requir$ re-%>p5+4 ,,! ,,murray ,,hill ,,tunnel4 ,! drift me?od ( excavat+ tunnels 0 foll[$ 9 ,section ,,iv ( ! ,new ,york ,subway1 "u ,p>k ,av5ue betwe5 #ccrd & #da/ ,/reets4 ,at ?is po9t ! f\r tracks ( ! subway pass "u a rocky elevation1 kn[n z ,murray ,hill1 9 two d\ble track p>allel tunnels1 #dc ft4 ap>t1 c5t] to c5t]4 ,"h already exi/$ a d\ble track tunnel :i* 0 built _m ye>s ago by ! ,new ,york ,c5tral & ,hudson ,riv] ,r4,r41 & is n[ us$ by ! ,madison ,av5ue surface c>s4 ,! two subway tunnels 7 driv5 close bel[ ! exi/+ tunnel & also v ne> ! f\ndations ( exp5sive resid5ces along ,p>k ,av5ue1 p>ticul>ly on ,murray ,hill1 "o ( ! be/ resid5tial sections ( ! city4 ,mat]ial ,p5etrat$4--,! mat]ial p5etrat$ by ! excavation consi/$ *iefly ( a surface outcrop ( ! mica-s*i/ rock :i* und]lies ,manhattan ,isl&4 ,! rock 0 = ! mo/ "p 9 compact /rata1 dipp+ at ab\t #de f ,ea/ to ,we/1 b at int]vals an un/able /ratum 0 enc\nt]$ :i* :5 free slid on ! und]ly+ /ratum4 ,tr\bles f su* slides 7 exp]i5c$ dur+ ! con/ruction ( ! tunnel4 ,cross-,section4--,! cross-section select$ = ! tunnels _h v]tical side walls & a ?ree-c5t]$ ro( ar* ) ! flatte/ curve at ! cr[n4 ,! int]ior dim5sions 7 #be ft4 wide & #af ft4 high4 ,! select$ cross-section 0 n ! be/ suit$ = a tunnel to be driv5 ?r\gh rock1 :]e ! %>pe/ curve %\ld be at ! top1 b 9 ?is case ! flatt5$ curve 0 *os5 because ( local conditions2 *iefly1 ! pres5ce ( ! exi/+ tunnel & ! consequ5t necessity ( leav+ a c]ta9 ?ickness ( rock betwe5 x & ! new tunnel1 )\t depress+ v mu* ! grade ( ! subway4 ,illu/ration3 ,,fig4 #eh4--,sequ5ce ( ,excavation 9 ! ,murray ,hill ,tunnel4 ,excavation4--,! two p>allel tunnels 7 driv5 exclusively f ! ends rea*$ by %afts2 ?us ! tunnels 7 attack$ at f\r p>ts4 ,x 0 9 ^! tunnels t a comp>ative te/ 0 made ( ! diff]5t me?ods ( driv+ tunnels ?r\gh rock4 ,! contractor appli$ ! head+ & drift me?od at ! s\!rn ends ( ! tunnels1 ! ea/]n tunnel be+ driv5 by means ( a drift :ile 9 ! we/]n tunnel ! usual head+ me?od 0 foll[$4 ,?is latt] me?od is illu/rat$ 9 ! *apt] foll[+ & ! ea/]n tunnel at #ccrd ,/reet1 excavat$ by means ( a drift1 is "h consid]$4 ,fig4 #eh %[s ! sequ5ce ( cuts adopt$ = ?is tunnel4 ,x 0 begun by a bottom drift1 ab\t #aj ft4 high1 #h ft4 wide & #g ft4 deep1 :i* 0 locat$ at "o side ( ! axis ( ! tunnel1 z indicat$ 9 ! figure4 ,?is drift 0 imm$iately wid5$ by remov+ ! portions m>k$ #b4 ,ab\t #ej ft4 9 ! re> ! "p m>k$ #c 0 tak5 away1 ?us cle>+ ! entire l[] portion ( ! tunnel4 ,section #d1 ab\t #ej ft4 to ! re> ( section #c1 0 !n brok5 d[n & remov$4 ,! me?ods ( drill+ & bla/+ 7 z foll[s3 ,9 tak+ out ! orig9al drift1 a w$ge-%ap$ c5t] cut 0 made & !n enl>g$ to ! full size ( ! drift by drill+ p>allel holes4 ,! succe$+ sections1 #b & #c1 7 remov$ by driv+ p>allel holes1 :ile ! top section1 #d1 0 tak5 away by a c5t] cut & p>allel holes4 ,! drills 7 m\nt$ on columns1 two drills to a column1 & ! holes 7 usually drill$ ab\t #g ft4 deep1 />t+ ) a diamet] ( #b 94 & end+ ) a diamet] ( #a 94 ,!y 7 bla/$ ) #dj dynamite 9 light *>ges1 only a few holes be+ fir$ at a "t1 usually n m ?an ?ree or f\r4 ,illu/ration3 ,,fig4 #ei4--,travel+ ,plat=m = ! ,excavation ( ! ,upp] ,side ( ! ,murray ,hill ,tunnel4 ,to remove section #d1 a travel+ plat=m #aj ft4 long & #be ft4 wide 0 us$4 ,?is plat=m1 z %[n 9 ,fig4 #ei1 consi/$ ( two longitud9al beams m\nt$ on f\r d\ble flang$ :eels :i* 7 runn+ on tracks laid #bc ft4 ap>t4 ,re/+ on top ( ^! beams 7 f\r #ab 94 #ab 94 uprights brac$ 9 e direction aga9/ ! framework ( ! plat=m4 ,?is frame 0 built ( #ab 94 #ab 94 beams laid longitud9ally1 ! transv]se beams be+ #ab 94 #ad ins4 ,! plat=m prop] 0 made ( #c 94 planks1 & 0 set #i ft4 above ! tunnel floor4 ,! columns support+ ! drills = ! excavation ( ! upp] section #d1 7 set up above ! plat=m :i* 0 !n re9=c$ by o!r v]tical props1 z indicat$ by ! dott$ l9es 9 ! figure4 ,^! props1 h[ev]1 7 plac$ s z to leave a cle>ance b5ea? ! plat=m = ! c>s to c>ry away ! dbris f ! front4 ,dur+ ! bla/+ ! plat=m 0 mov$ back s t ! bla/$ rock fell to ! floor ( ! tunnel1 :5ce x 0 load$ into boxes on ! c>s4 ,/rutt+4--,:5 ! rock 0 seamy & full ( fissures1 runn+ 9 e direction1 x 0 necess>y to support ! ro( ( ! excavation4 ,?is 0 done 9 ! foll[+ mann]3 ,aft] "p #d 0 remov$ ! timb]s support+ ! ro( ( ! excavation 7 set up4 ,9 ?is case1 ! polygonal /rutt+ 0 us$4 ,?is consi/$ ( heavy timb] frames plac$ transv]sely to ! axis ( ! tunnel & support+ ! planks or pol+-bo>ds :i* ran longitud9ally aga9/ ! ro( ( ! excavation4 ,! sev5-segm5t ar* frame 0 us$ 9 ! ,murray ,hill tunnel4 ,at ! bottom ( "p #d 7 plac$ longitud9ally #ab #af 94 beams & ^u !m re/$ ! incl9$ segm5ts :i*1 ) a horizontal "o1 =m$ ! ar* frame z %[n 9 ,fig4 #fj4 ,:5 ! pressures 7 too heavy ! cr[n segm5t 0 re9=c$ by a #f #ab 94 beam1 kept 9 place by two #ab #ab 94 incl9$ props :i* re/$ on ! templates4 ,z ! tunnel 0 l9$ ) concrete1 ! timb]+ 0 left 9 place & x 0 built outside ! l9e ( ! extrados ( ! concrete l9+4 ,timb]+ 0 only us$ = a %ort di/ance b x necessitat$ a l>g] am\nt ( rock excavation :5 x 0 requir$4 ,illu/ration3 ,,fig4 #fj4--,timb]+ ,us$ 9 ! ,murray ,hill ,tunnel4 ,haul+4--,great effici5cy 0 %[n 9 ! me?od ( haul+ away ! excavat$ mat]ials4 ,?ree n>r[-gauge p>allel tracks 7 laid on ! floor ( ! tunnel & ext5d$ to ! faces ( ! advance drifts4 ,small flat c>s 7 run on ^! tracks4 ,!y c>ri$ /eel boxes1 #e ft4 squ>e & #ae ins4 deep1 fitt$ ) ?ree lift+ r+s & *a9s4 ,:5 fill$1 ! c>s 7 run to ! bottom ( ! %aft1 ! boxes 7 hoi/$ by a /iff-legg$ d]rick plac$ at ! %aft head1 & ! dbris 0 dump$ into /orage b9s ( #cjj cu4 yds4 capacity4 ,^! b9s 7 elevat$ #h ft4 above ! /reet s t ! wagons c\ld be driv5 "u x to take loads ( spoil by means ( *utes4 ,! brok5 rock 0 load$ into ! boxes by h&4 ,concrete ,l9+4--,! tunnel 0 l9$ ) concrete :i* 0 manufactur$ by a q elaborate plant4 ,a /one cru%+ plant1 consi/+ ( b9s = raw & cru%$ /one1 0 erect$ at ! %aft head & a mix+ plant 0 susp5d$ f ! %aft4 ,on ! plat=m ( ! %aft head 7 two b9s side by side1 "o = cru%$ /one1 ! o!r = s&2 bo? ( :i* communicat$1 by means ( trap doors1 ) a hopp] *ute4 ,! mat]ials f ! hopp] 7 deliv]$ into a measur+ box :]e cem5t 0 laid on top ( ! o!r +r$i5ts by h&4 ,!y 7 !n convey$ ?r\gh a canvas *ute into a cubical mix] op]at$ by an eng9e4 ,! mix] dis*>g$ its cont5ts into skips set on c>s at ! bottom ( ! %aft & ! concrete 0 haul$ inside ! tunnel ready = use4 ,! con/ruction ( ! l9+ 0 accompli%$ by means ( travel+ plat=ms4 ,! foot+ c\rses 7 laid fir/4 ,because ^! project$ inw>d ab\t #ah ins4 f ! faces ( ! f9i%$ sidewalks x 0 possible to lay a track rail on _! top inn] edges on ea* side ( ! tunnel4 ,^! track rails c>ri$ ! travel+ plat=ms4 ,!re 7 ?ree ( ^! plat=ms2 ! =w>d "o 0 us$ = build+ ! side walls2 ! c5t] "o1 = c>ry+ a d]rick2 ! la/ "o1 = build+ ! ro( ar*4 ,! side wall plat=m 0 m\nt$ on six :eels4 ,on ea* side !re 0 m\nt$ an adju/able lagg+ :i* 0 curv$ to con=m to ! inside pr(ile ( ! side wall4 ,9 op]ation ?is plat=m 0 run to ! po9t :]e ! side walls 7 to be con/ruct$ & ! lagg+ 0 adju/$ to position & fa/5$4 ,skips ( concrete 7 !n hoi/$ on its top1 _! cont5ts 7 %ovel$ into ! space betwe5 ! lagg+ & ! wall ( ! excavation & 7 !re ramm$ into place until ! f9i%$ concrete _h rea*$ ! top ( ! lagg+4 ,:5 ! concrete _h set1 ! w$ges hold+ ! lagg+ 9 place 7 loos5$ & ! plat=m 0 mov$ ahead & adju/$ = build+ a new section ( wall4 ,! d]rick plat=m 0 #bc ft4 wide & #ah ft4 long4 ,transv]sely1 x _h ?ree bays1 two ( :i* 7 floor$ ov] & "o 0 left )\t floor+ to all[ passage = ! concrete skips to & f ! c>s1 on ! tunnel floor b5ea?4 ,at ! c5t] ( ! floor$ area 0 m\nt$ a d]rick to h&le ! skips4 ,9 op]ation1 ! d]rick plat=m came betwe5 ! side wall plat=m ahead & ! ro( plat=m beh9d4 ,! con/ruction ( ! ro( plat=m 0 practically ! same z ! side wall plat=m ) ! addition ( ro( ar* c5t]s at ea* b5t on :i* lagg+ c\ld be plac$4 ,! mode ( proc$ure 0 to erect ! =m = a small space betwe5 ! side walls already built & ! haun*es ( ! c5t]1 to %ovel concrete f ! skips & to run x into place4 ,!n ! ro( lagg+1 a "p at a "t1 0 plac$ upw>d f ! haun*es & ! concrete 0 fill$ & ramm$ beh9d x4 ,! l9+ 0 built f ! haun*es upw>d until ! two sides approa*$ )9 a di/ance ( ab\t #e ft4 f ea* o!r at ! cr[n4 ,?is #e ft4 cr[n /rip or key 0 built by work+ f ! re> t[>d ! front end ( ! plat=m4 ,plant4--,! plant us$ by ! contractors = ,section ,,iv4 ( ! subway compris$ a c5tral p[] plant locat$ ab\t #djjj ft4 f ! "w4 ,?is 0 on #dbnd ,/reet ne> ! ,ea/ ,riv] & furni%$ p[] = ! "w on bo? ,sections ,,iv4 & ,v4 ,! build+s consi/$ ( an eng9e room #fc #cj ft4 & a boil] room1 #db #bh ft4 ,9 ! =m] room 0 locat$ "o ,r&-,corliss air compressor1 #bb #dj #dh ins41 hav+ a capacity ( #ejjj cu4 ft4 ( free air p] m9ute2 9 ! latt] room !re 7 two #bjj ,h4,p4 wat] tube boil]s4 ,!re 7 also ! necess>y equipm5t ( fe$ wat] pump1 air cond5s] pump1 etc4 ,! compressors dis*>g$ into a #bj #e ft4 receiv] ( rivet$ /eel ?r\gh a #g 94 pipe4 ,! air f ! receiv] 0 c>ri$ by a #aj 94 pipe #c4bgg ft4 to ! corn] ( ,p>k ,av5ue & #da/ ,/reet1 & 0 !nce run s\? along ,p>k ,av5ue 9 an #h 94 pipe1 f :i* #c 94 bran*es l$ to ! f\r head+s ( ! "w4 ,v5tilation4--,! v5tilation ( ! tunnel caus$ v little tr\ble4 ,9 cool wea!r ! natural draft ( ! %afts & ! air dis*>g$ f ! drills s]v$ to keep ! atmosph]e :olesome4 ,9 w>m wea!r1 artificial means 7 necess>y to cle> ! work+s ( f\l air1 p>ticul>ly aft] bla/+4 ,!y compris$ at ea* end a #d ft4 ,am]ican exhau/ fan draw+ air f a #ab 94 rivet$ galvaniz$ iron pipe1 :i* ext5d$ to ! work+ faces4 ,illum9ation4--,! tunnel 0 light$ by electric lamps :i* ext5d$ ev5 to ! work+ face4 ,dur+ ! bla/+1 h[ev]1 all ! lamps & wires )9 #ajj ft4 f ! front 7 remov$ & gasol9e tor*es 7 us$2 !y 7 also employ$ be=e ! electric lamps & wires c\ld be replac$1 to light ! tunnel dur+ ! op]ation ( cle>+ ! dbris4 ,,*apt] ,,xi4 ,,tunnels ,,?r\gh ,,h>d ,,rock 7,cont9u$74--,,excavation ,,by ,,head+s4 ,,european ,,& ,,am]ican ,,me?ods4 ,! m common me?od ( tunnel+ ?r\gh h>d rock is to beg9 ! "w by a head+1 in/ead ( by a drift4 ,?is head+ may be ( small dim5sions1 & ! rema9d] ( ! section may also be remov$ 9 successive small p>ts1 or x may be ! full wid? ( ! section1 & ! enl>gem5t ( ! section be made 9 "o o!r cut4 ,illu/ration3 ,,fig4 #fa4--;,diagram ,%[+ ,sequ5ce ( ,excavation 9 ,head+ ,me?od ( ,tunnel+ ,rock4 ,g5]al ,discussion4--,:5 ! tunnel is excavat$ by means ( sev]al cuts1 :i* is ! me?od usually employ$ 9 ,europe1 ! sequ5ce ( "w is z indicat$ by ,fig4 #fa4 ,"w is begun by driv+ ! c5t] top head+ ,no4 #a1 ^: floor is at ! level ( ! bottom ( ! ro( ar*1 & :i* is usually excavat$ by ! circul> cut me?od4 ,?is head+ is wid5$ by remov+ p>ts ,nos4 #b & #c until ! top "p ( ! section is remov$1 !n ! ro( ar* is built ) its feet re/+ on ! unexcavat$ rock bel[4 ,! l[] portion ( ! section or b5* is remov$ by fir/ s9k+ ! tr5* ,no4 #d1 aft] :i* "p ,no4 #e is tak5 out1 & !n p>ts ,nos4 #f & #g1 & ! side walls built4 ,"p ,no4 #h = ! culv]t is f9ally op5$4 ,! head+ is1 z a rule1 driv5 f> 9 advance1 b ! excavation ( ea* ( ! o!r p>ts foll[s ! prec$+ "o at a di/ance beh9d ( ab\t #cjj ft4 ,! /rutt+1 :5 any is requir$1 is usually ! typical radial /rutt+ ( ! ,belgian me?od ( tunnel+4 ,! masonry l9+ is con/ruct$ practically ! same z 9 tunnels excavat$ by a drift4 ,! haul+ is done on a s+le track laid 9 ! head+ ,no4 #a1 :i* sep>ates into d\ble tracks :]e ! full top section has be5 excavat$ by ! removal ( p>ts ,no4 #b4 ,^! two tracks are aga9 comb9$ & =m a s+le track along ! top ( "p ,no4 #e1 :i* has be5 left wid] ?an "p ,no4 #d = ?is p>ticul> purpose4 ,:5 "p ,no4 #c is excavat$ a /&>d-gauge track is laid on its floor2 & z ! full section ( ! tunnel is complet$ by tak+ out p>ts ,nos4 #d & #e1 ?is s+le track is replac$ by two /&>d-gauge tracks1 into :i* x swit*es4 ,spoil is transf]r$ f ! n>r[-gauge tracks on ! upp] level1 to ! /&>d-gauge tracks on ! tunnel floor1 by means ( *utes1 & build+ mat]ial is transf]r$ 9 ! opposite direction by means ( hoi/+ app>atus4 ,:5 ! excavation is made by a s+le wide head+1 & a s+le o!r cut = remov+ ! b5*1 :i* is ! me?od pref]r$ by ,am]ican eng9e]s1 x is call$ ! ,head+ & ,b5* me?od4 ,! "w beg9s by remov+ a top head+ ! full wid? ( ! section2 ?is head+ is usually made #g ft4 or #h ft4 high1 & is excavat$ by ! c5t] cut me?od4 ,! me?od ( /rutt+ usually employ$ is to erect successive ?ree- or five-segm5t timb] ar*es1 ^: feet re/ on ! top ( ! b5*2 :5 ! b5* is remov$1 po/s are ins]t$ "u ! feet ( ea* ar*4 ,^! ar*es are cov]$ ) a lagg+ ( plank4 ,9 ,am]ica x has (t5 be5 ! practice to let ?is /rutt+ s]ve z a tempor>y l9+1 & to replace x only aft] "s "t1 (t5 aft] ye>s1 ) a p]man5t l9+ ( masonry4 ,9 a succe$+ *apt]1 "s ( ! me?ods adopt$ 9 rel9+ timb]-l9$ ar*es ) masonry are describ$4 ,! haul+ is done by ei!r n>r[ or broad gauge tracks laid on ! floor ( ! complet$ section bel[4 ,a device call$ a b5* c>riage is (t5 employ$ to enable ! c>s runn+ on ! head+ tracks to dump _! loads into ! c>s bel[1 )\t int]f]+ ) ! "w on ! b5* front4 ,?is device consi/s ( a wide plat=m c>ri$ on trucks1 runn+ on rails at ! sides ( ! tunnel floor1 s t x is level ) ! floor ( ! head+4 ,! front ( ?is plat=m c>ries a h+$ leaf :i* may be rais$ & l[]$1 & :i* =ms a sort ( gang-plank rea*+ to ! floor ( ! head+4 ,by runn+ ! head+ c>s out on to ?is travel+ plat=m1 !y c be dump$ into ! c>s bel[ entirely cle> ( ! "w 9 progress on ! b5* front4 ,= ! purpose ( illu/rat+ ! two me?ods ( driv+ tunnels by a head+1 :i* h be5 briefly describ$1 ! ,/4 ,go?>d & ! ,=t ,george tunnels h be5 select$4 ,! ,/4 ,go?>d tunnel is select$1 z be+ "o ( ! longe/ tunnels 9 ! _w1 & because x 0 excavat$ by a numb] ( small p>ts2 & ! ,=t ,george tunnel1 z be+ a d\ble-track tunnel1 driv5 by a head+1 & b5*1 & hav+ a concrete l9+4 ,,/4 ,,go?>d ,,tunnel4 ,! ,/4 ,go?>d tunnel p5etrates ! ,alps betwe5 ,italy & ,france1 & is #i miles long4 ,x 0 con/ruct$ 9 #ahgb-hb4 ,mat]ial ,p5etrat$4--,! ,/4 ,go?>d tunnel 0 excavat$ ?r\gh rock1 consi/+ *iefly ( gneiss1 mica-s*i/1 s]p5t9e1 & hornbl5de1 ! /rata hav+ an incl9ation ( f #de to #ij4 ,at _m po9ts ! rock 0 fissur$1 & dis9tegrat$ easily1 & wat] 0 enc\nt]$ 9 l>ge quantities1 caus+ mu* tr\ble4 ,excavation4--,! sequ5ce ( excavation is %[n by ,fig4 #ad1 p4 #cf4 ,fir/ ! top c5t] head+1 ,no4 #a1 ^: dim5sions v>i$ f #h4be #h4f ft4 to #h4e #i ft41 accord+ to ! quality ( ! rock1 0 driv5 nev] less ?an #ajjj ft4 & sometimes ov] #cjjj ft4 9 advance ( p>ts ,no4 #b4 ,! excavation ( p>ts ,no4 #b op5$ up ! full top section1 & p>ts ,nos4 #c1 #d1 #e1 #f1 & #g1 7 remov$ 9 ! ord] numb]$4 ,/rutt+4--,:]e regul> /rutt+ 0 requir$1 ! con/ruction %[n 9 ,fig4 #fb 0 adopt$4 ,masonry4--,! ,/4 ,go?>d tunnel is l9$ ?r\gh\t ) masonry4 ,aft] ! upp] portion ( ! section 0 fully excavat$1 ! ro( ar* 0 built ) its feet re/+ ^u %ort planks on ! top ( ! b5*4 ,plank c5t]s 7 us$ 9 con/ruct+ ! ar*4 ,= ! ar* brick masonry 0 employ$1 b ! side walls 7 built ( rubble masonry4 ,%elt] ni*es1 ab\t #c ft4 deep1 7 built into ! side walls at int]vals1 & ab\t e #c1jjj ft4 /orage ni*es ab\t #aj ft4 deep1 & clos$ ) a door1 7 con/ruct$4 ,! culv]t 0 ( brick masonry4 ,me*anical ,in/allation4--,wat]-p[] 0 us$ exclusively 9 driv+ ! ,/4 ,go?>d tunnel4 ,at ! nor? end1 ! ,reuss1 & at ! s\? end1 ! ,tess9 & ! ,tremola1 riv]s or torr5ts 7 damm$1 & _! wat]s conduct$ to turb9e plants at ! opposite ends ( ! tunnel4 ,! p[] ?us furni%$ by ! ,reuss 0 ab\t #a1ejj ,h4,p41 & ! p[] furni%$ by ! comb9$ supply ( ! ,tess9 & ,tremola 0 #a1bbj ,h4,p4 ,! turb9e plant at bo? ends at fir/ consi/$ ( f\r horizontal impulse turb9es1 b lat]1 two m turb9es 7 add$ at ! s\? end4 ,ea* ( ! two sets ( f\r turb9es fir/ in/all$ drove five gr\ps ( ?ree compressors ea*1 & ! two supplem5t>y turb9es drove two gr\ps ( f\r compressors ea*4 ,! compressors 7 ( ! ,colladon type ) wat] injection1 & f\r gr\ps ( ?ree compressors ea* 7 capable ( furni%+ #a1jjj cu4 yds4 ( air compress$ to betwe5 sev5 & eight atmosph]es e h\r1 or ab\t #ajj ,h4,p4 p] h\r1 deliv]$ to ! drills at ! front4 ,?is air :5 exhau/$ provid$ ab\t #h1jjj cu4 yds4 ( fre% air p] h\r = v5tilation4 ,! compressors at ea* entrance dis*>g$ into a gr\p ( f\r cyl9drical receiv]s ( wr\ght-iron ea* #e4c ft4 9 diamet] by #bi4e ft4 long1 & hav+ a capacity ( #eic cu4 ft4 ,! cyl9d]s 7 plac$ horizontally1 ! fir/ "o receiv+ ! air at "o end & dis*>g+ x at ! o!r end into ! next cyl9d]1 & s on4 ,by ?is arrangem5t ! air 0 dra9$ ( its moi/ure1 & ! dis*>ge f ! end receiv] into ! tunnel deliv]y pipes 0 n affect$ by ! pulsations ( ! compressors4 ,! deliv]y pipe decreas$ f #h 94 9 diamet] at ! receiv] to #d ins4 9 diamet]1 & f9ally to #b ins4 9 diamet]1 at ! front4 ,! drills employ$ 7 ( v>i\s patt]ns4 ,! fir/ "o employ$ 0 ! ,dubois ,franois 8p]=ator10 9 :i* ! drill-bit 0 f$ =w>d by h&4 ,?is 0 replac$ by ,f]r\x drills hav+ an automatic fe$4 ,jules ,mc,kean's 8p]=ator0 0 employ$ at ! nor? end ( ! tunnel4 ,all ( ^! drills 7 ( ! p]cussion type1 & 7 m\nt$ on c>riages runn+ on tracks4 ,_! comp>ative effici5cy 0 (ficially te/$ 9 drill+ granitic gneiss ) an op]at+ air pressure ( #e4e atmosph]es ) ! foll[+ results3 ,,"n ,,( ,,drill4 ,,p5etration ,,ins4 ,,p] ,,m94 ,f]r\x #a4f ,mc,kean #a4d ,dubois ,franois #a4jd ,s\mmeli] #j4he ,! head+ 0 excavat$ by ! circul> cut me?od1 ! holes be+ driv5 z foll[s3 ,ne> ! c5t] ( ! head+ ?ree holes 7 fir/ drill$1 conv]g+ s z to inclose a pyramid ) a triangul> base4 ,ar\nd ^! c5t] holes f #i to #ac o!rs 7 driv5 p>allel to ! tunnel axis4 ,! c5t] holes 7 bla/$ fir/1 & !n ! surr\nd+ holes4 ,f #c to #e h\rs 7 requir$ to drill ! two sets ( holes1 & f ?ree to f\r h\rs 7 requir$ to remove ! bla/$ rock4 ,! numb] ( holes drill$ 9 remov+ ea* ( ! v>i\s p>ts 0 z foll[s3 ,"p ,no4 #a #f to #i ,"p ,no4 #b #f to #aj ,"p ,no4 #c #b ,"p ,no4 #d #f to #i ,"p ,no4 #e #c ,"p ,no4 #f #f to #i ,"p ,no4 #g #a -------- ,total = full section #cf to #dj ,haul+4--,two diff]5t sy/ems 7 employ$ = haul+ ! spoil & con/ruction mat]ial 9 ! ,/4 ,go?>d tunnel4 ,to remove ! spoil f p>ts ,nos4 #a & #b a n>r[-gauge track 0 laid on ! floor ( ! head+1 & ! c>s 7 haul$ by horses1 ! grade be+ desc5d+ f ! fronts4 ,^! n>r[-gauge c>s 7 dump$ into l>g] broad-gauge c>s runn+ on ! track laid on ! floor ( ! complet$ section & haul$ by compress$ air locomotives 7,fig4 #fc74 ,to raise ! incom+ /ructural mat]ial f ! broad-gauge c>s to ! n>r[-gauge c>s runn+ on ! level above1 hoi/+ devices 7 employ$4 ,illu/ration3 ,,fig4 #fb4--,me?od ( ,/rutt+ ,ro(1 ,/4 ,go?>d ,tunnel4 ,illu/ration3 ,,fig4 #fc4--,sket* ,%[+ ,arrangem5t ( ,c> ,tracks1 ,/4 ,go?>d ,tunnel4 ,,=t ,,george ,,tunnel4#aj ,f a po9t nor? ( #aeg? ,/reet & ,broadway almo/ to ,dyckman ,/reet1 t is1 a di/ance ( ne>ly two miles1 ! ,new ,york ,subway passes "u an elevation kn[n z ,=t ,wa%+ton ,heights1 :i* almo/ b\nds ,manhattan ,isl& at its upp] end ne> ! ,h>lem ,%ip ,canal4 ,"u ?is elevation ! rapid transit railroad 0 con/ruct$ 9 tunnel4 ,! tunnel 0 driv5 f two int]m$iate %afts ov] #aaj ft4 deep1 locat$ "o at #afi? ,/reet & ! o!r at #aha/ ,/reet & ,broadway4 ,bo? %afts 7 sunk at "o side ( ! c5t] l9e ( ! tunnel4 ,aft] ^! %afts _h be5 utiliz$ = work+ purposes dur+ ! con/ruction ( ! tunnel1 !y 7 equipp$ ) electric elevators to c>ry pass5g]s f ! /reets to ! deep /ation4 #aj ,cond5s$ f a pap] by ,/eph5 ,w4 ,hopk9s 9 ,h>v>d ,eng9e]+ ,j\rnal1 ,april1 '#jh4 ,mat]ial4--,! mat]ial enc\nt]$ 9 ! excavation ( ! ,=t ,george tunnel 0 ! usual mica s*i/ met ev]y:]e on ,manhattan ,isl&4 ,x 0 full ( seams ) /rata runn+ 9 e direction to su* an ext5t t at _m po9ts ! ro( ( ! tunnel _h to be support$ by timb]s2 at o!r p>ts along ! l9e ! rock 0 s dis9tegrat$ t x 0 consid]$ a v loose & trea*]\s soil4 ,two s]i\s accid5ts1 ea* accompani$ by loss ( life1 occurr$ dur+ ! con/ruction ( ?is tunnel4 ,bo? ( !m 7 caus$ by ! sudd5 fall ( a l>ge l$ge ( rock :i*1 aft] ! tunnel _h be5 excavat$ to ! full section1 rema9$ hang+ on ! ro(1 depriv$ ( any support & held 9 place by ! little cohesion ( ! mat]ial pack+ ! seams4 ,excavation4--,! tunnel 0 excavat$ by ! head+ me?od 9 only two cuts1 viz41 ! head+ & b5* z indicat$ 9 ! ,fig4 #fe4 ,! head+1 almo/ z wide z ! upp] portion ( ! tunnel section1 0 excavat$ 9 ! mann] expla9$ on page #ia4 ,aft] ! head+ 0 remov$1 ! enl>gem5t ( ! entire upp] section ( ! tunnel 0 accompli%$ by driv+ ?ree incl9$ holes at ea* side ( ! head+4 ,!y 7 driv5 at diff]5t dep?s & incl9ations1 z %[n 9 ! figure & 7 call$ trimm+ holes4 ,at ! same "t ! b5* 0 remov$ by means ( five holes--?ree v]tical & two incl9$4 ,! l9e ( subgrade 0 rea*$ by means ( five grad+ holes driv5 almo/ horizontal ) a slight incl9ation d[nw>d4 ,! air drills = ! head+ 7 m\nt$ on columns1 all ! o!rs on tripods4 ,! bla/+ 0 done 9 ! foll[+ ord]3 ! grad+ holes 7 bla/$ 9 ! fir/ r\nd1 ! b5* & trimm+ 9 ! second1 ! c5t] cut ( ! head+ 9 ! ?ird1 ! sides 9 ! f\r? & ! dry holes 9 ! la/4 ,?us ea* advance ( #g ft4 ( ! :ole tunnel section 0 made by means ( =ty holes fir$ 9 five r\nds :i* consum$ #bgg lbs4 ( dynamite ) an av]age additional quantity ( #gf lbs41 mak+ a total ( #cec lbs4 ,) ! exception ( ! c5t] cut1 :]e #fj dynamite 0 us$1 all ! o!r holes 7 dis*>g$ ) #dj dynamite4 ,illu/ration3 ,cross ,section4 ,longitud9al ,section4 ,,fig4 #fd4--;,arrangem5t ( ,drill ,holes 9 ! ,=t ,george ,tunnel4 ,,fig4 #fe4--,longitud9al ,section ( ! ,head+ & ,b5* ,excavation at ! ,=t ,george ,tunnel4 ,/rutt+4--,:5 ! rock 0 ( su* a "* z to be dang]\s & requir$ p]man5t timb] support1 until ! masonry l9+ 0 9 place1 ! me?od employ$ 0 z foll[s3 a top head+ 0 fir/ excavat$ ab\t #aj ft4 deep & f #aj ft4 to #ab ft4 wide = "s di/ance1 #ajj ft4 to #ejj ft41 ! dang]\s rock be+ support$ by #aj #aj 94 yell[ p9e plumb or rak+ po/s & sometimes by timb] b5ts 78caps & legs074 ,! next process 0 to wid5 ! head+ to ! full wid? ( #cj ft4 = a l5g? ( ab\t #bj ft41 plac+ timb] supports "u ! dang]\s rock z ! wid5+-out progress$4 ,! excavation 0 deep5$ a little at ! sides to #i4e ft4 bel[ ! ro( grade 7ord]$ l9e ( excavation7 or ab\t #aa ft4 bel[ ! ro( grade1 :i* 0 necess>y :5 segm5tal timb]+ 0 to be us$1 to all[ = plac+ a #ab #ab 94 8wall plate0 7timb] sill7 along ea* side4 ,^! wall plates1 g5]ally #bj ft4 long1 7 set to ! correct elevation & 7 level$ by block+ & w$g+4 ,z soon z ! wall plates 7 set1 ! "w ( erect+ ! segm5tal timb] sets1 "o set at a "t1 0 begun by />t+ f ! wall plates & support+ ! timb] on scaffold+ until key$ 91 !n x 0 block$ up to ! rock at ea* jo9t & at o!r necess>y po9ts4 ,:5 two or m sets 7 erect$1 lagg+1 made ( bo>ds #b ins4 ?ick by #f to #aj ins4 wide1 0 plac$ ov] ! segm5tal timb] 8sets0 & ! space above ! timb] dry pack$ ) small /one plac$ by h&4 ,sometimes !re 0 en\gh room betwe5 ! timb] & ! rock to d all ! dry pack+ aft] ! full numb] ( sets1 g5]ally six1 _h be5 plac$ on ! two wall plates4 ,! tempor>y timb] po/s & braces 7 tak5 out z ! segm5tal timb] sets 7 erect$4 ,! sev5 timb]s t made up a timb] set 7 ( yell[ p9e ea* #aj #aj ins41 #e ft4 #b ins4 long at ! intrados & #e ft4 #f ins4 at ! extrados4 ,! sets 7 spac$ f #c ft4 to #e ft4 ap>t1 b g5]ally #c4e ft4 & brac$ to ea* o!r at ea* jo9t ( ! segm5tal timb]s by #f #h 94 spread]s :i* 7 w$g$ aga9/ ! jo9t splices4 ,:5 ! timb]s 7 all erect$ on a set ( wall plates 7#bj ft47 & ! lagg+ & dry pack+ 7 complet$ ! "w ( tak+ out ! b5*1 :i* _h be5 p>tly drill$ z ! timb] sets 7 erect$1 0 resum$4 ,! face ( ! b5*1 :i* _h be5 left ab\t #d ft4 f ! end ( ! previ\s set ( wall plates1 0 br\ght =w>d sl[ly by plac+ #aj #aj 94 plumb po/s :i* ext5d$ bel[ subgrade "u ! wall plates4 ,^! po/s 7 g5]ally spac$ ! same z ! timb] sets above & directly "u !m4 ,:5 ! face ( ! b5* _h be5 br\ght to )9 #c or #d ft4 ( ! =w>d end ( ! wall plate1 ! process ( wid5+ out & timb]+ ano!r #bj ft4 l5g? ( head+ 0 begun4 ,9 "s places ! rock1 ?\gh ne$+ p]man5t support1 0 su* t ! "w ( tak+ out ! b5* & wid5+ ! head+ 0 c>ri$ on simultane\sly )\t increas+ ! dang]2 b ! great] portion ( ! "w1 :5 /rutt+ 0 requir$1 0 done z has be5 describ$4 ,illu/ration3 ,,fig4 #ff4--;,diagram ,%[+ ! ,arrangem5t ( ,drill ,holes 9 ! ,head+ & ,b5* ( ! ,gallits9 ,tunnel4 ,haul+4--,! excavat$ mat]ial 0 load$ at ! foot ( ! b5* 9 dump c>s :i* 7 run by mule p[] to ! portal or ! %aft accord+ to location1 on #cf 94 gauge-s]vice tracks4 ,incl9es at #aei? ,/reet 7 grad$ f ! portal at #aeh? ,/reet to ! /reet surface4 ,! c>s 7 =m$ at ?is portal into a tra9 & 7 tak5 up ! incl9e to ! dump at #afbnd ,/reet & ! ,nor? ,riv] by con/ruction locomotives4 ,at ! #afh? ,/reet & #aha/ ,/reet %afts1 ! c>s 7 hoi/$ to ! surface 9 cages 7elevators74 ,9 ! =m] case1 !y 7 tak5 to ! dump at #afe? ,/reet & ! ,nor? ,riv] by mules & gravity2 9 ! latt] case1 to v>i\s dumps by teams4 ,at bo? %afts1 /one cru%]s 7 locat$1 !re=e a great "p ( ! mat]ial did n h to be haul$ to ! dumps or ev5 tak5 to ! surface z a great deal ( /one 0 us$ 9 dry pack+ ov] ! concrete ar*4 ,! mat]ial f ! portal at ,=t ,george 0 haul$ by mules directly to ! dump ne> by4 ,l9+4--,! entire tunnel 0 l9$ ) concrete1 consi/+ ( a floor #d ins4 ?ick & v]tical side walls #ah ins4 ?ick & #be ft4 ap>t1 :i* c>ri$ a semicircul> ar* #ah ins4 ?ick except 9 ! timb]$ portions :]e ! ?ickness 0 increas$ to #ba ins4 & to #bd & #bg ins4 9 "s places4 ,! spr++ l9e ( ! ar* is #f ft4 #b ins4 above ! concrete floor 7#e ft4 #f ins4 above ! base ( rail71 h5ce ! maximum cle>ance above ! base ( rail is #ah ft4 ,! side walls & ar* 7 built solid ( rock to a height ( #h ft4 above spr++ l9e & ! space above t po9t betwe5 ! concrete & ! rock 0 pack$ by h& ) small /ones4 ,! concrete ( ! ar* 0 laid on timb] c5t]s erect$ = t purpose4 ,! head+ & b5* me?od ( excavat+ rock tunnels is n always foll[$ 9 ! mann] j describ$ b is employ$ ) slight modifications4 ,!re is a l>ge v>iety ( modifications b only ! two mo/ commonly us$ 9 practical works are giv5 "h4 ,! head+ & b5* me?od illu/rat$ 9 ,fig4 #ff 0 us$1 among o!rs1 on ! ,gallits9 tunnel along ! ,p5nsylvania ,r4,r4 at ! summit ( ! ,allegh5ies ne> ,altoona1 ,pa41 & m rec5tly 9 ! tunnels con/ruct$ by ! same company "u ,b]g5 ,hill1 ,n4 ,j41 = ! entrance to ,new ,york ,city4 ,! %ape ( ! cross-section ( ^! tunnels 0 semicircul> ar* on v]tical side walls4 ,! excavation 0 made 9 ?ree consecutive cuts1 viz41 ! head+ m>k$ #a 9 ! figure1 ! top b5* #b1 & ! l[] b5* #c4 ,a head+ #g ft4 high & #aj ft4 wide 0 atta*$ ne> ! cr[n ( ! ar* & ! rock 0 remov$ by means ( a c5t] cut & p>allel side holes1 ! numb] ( holes dep5d+ ^u ! consi/5cy ( ! rock4 ,! "p ,no4 #b 0 excavat$ by drill+ holes at ea* side to diff]5t dep?s & at diff]5t incl9ations 9 ord] to rea* ! l9e ( ! pr(ile z well z ! spr++ l9e ( ! propos$ tunnel4 ,! c5tral "p ( ! top b5* 0 excavat$ by means ( holes driv5 v]tically f ! floor ( ! head+4 ,! bottom b5* ,no4 #c1 includ$ betwe5 ! spr++ l9e ( ! ar* & subgrade1 0 remov$ by means ( five v]tical holes driv5 f ! floor ( ! top b5*4 ,! ?ree diff]5t work+ p>ts 7 kept ne>ly #aj ft4 ap>t4 ,bla/+ 0 effect$ 9 rev]s$ ord] to ! figures m>k$ 9 ! diagram1 viz41 ! bottom b5* fir/ & ! head+ la/4 ,illu/ration3 ,,fig4 #fg4--;,diagram ,%[+ a ,modification ( ! ,head+ & ,b5* ,me?od4 ,/ill ano!r modification ( ! head+ & b5* me?od1 commonly foll[$ by ,am]ican eng9e]s1 is ! "o %[n 9 ,fig4 #fg4 ,?is consi/s 9 divid+ ! tunnel section 9 ?ree p>ts by horizontal l9es4 ,! resultant p>ts are fir/ ! head+ excavat$ close to ! ro(1 & z wide z ! :ole section ( ! tunnel2 second1 ! top b5* 9 ! middle1 & la/ly ! bottom b5* excavat$ to ! dep? ( ! propos$ tunnel floor4 ,! excavation proce$s 9 ! num]ical ord]1 beg9n+ at ! head+ :i* 0 excavat$1 z usual1 by means ( a c5t] cut & side holes to ! full wid? ( ! propos$ tunnel4 ,fir/ ! top b5*1 !n ! bottom b5*1 are remov$ by means ( v]tical holes driv5 f ! floor ( ! head+ & ! floor ( ! top b5*1 respectively4 ,,comp>ison ,,( ,,me?ods4 ,! diff]5ces betwe5 ! drift & head+ me?ods ( excavat+ tunnels ?r\gh rock1 consi/ *iefly 9 ! excavations1 /rutt+1 & haul+4 ,:5 ! drift me?od is employ$ an advanc$ gall]y is op5$ along ! floor ( ! tunnel be=e ! upp] "p ( ! section is remov$1 & :5 ! head+ me?od is employ$ ! upp] "p ( ! section is completely excavat$ be=e any "p ( ! section bel[ is excavat$4 ,:5 ! drift me?od ( driv+ is employ$ polygonal /rutt+ is usually us$1 & longitud9al /rutt+ is employ$ ) ! head+ me?od ( driv+4 ,9 ! drift me?od ! haul+ is done by "o sy/em ( tracks at ! same level1 :ile 9 ! head+ me?od two sy/ems ( tracks are employ$ at diff]5t levels4 ,x is1 p]haps1 impossible to /ate )\t qualification :i* me?od is ! bett]4 ,european eng9e]s :o h be5 connect$ ) bo? ! ,mont ,c5is & ,/4 ,go?>d tunnels1 driv5 by ! drift & head+ me?ods respectively1 _h ! opportunity to practically obs]ve ! advantages & disadvantages ( ^! two me?ods4 ,_! conclusion 0 t ! drift me?od 0 m conv5i5t = tunnels driv5 ?r\gh h>d & compact rock1 & t ! head+ me?od 0 bett] = tunnels ( fissur$ & dis9tegrat$ rocks4 ,to prove ?is op9ion1 exp]im5ts 7 made 9 "o ( ! tunnels approa*+ ! great ,/4 ,go?>d tunnel4 ,on a %ort tunnel ! excavation 0 made by ! drift me?od f "o portal1 :ile at ! o!r1 ! head+ me?od 0 foll[$4 ,al?\gh ! g5]al rule 0 fully confirm$ /ill ! conditions at ! portals 7 n id5tical4 ,m conclusive exp]im5ts 7 made by ,mr4 ,ira ,a4 ,%al]1 ! contractor = ,section ,,iv41 ( ,new ,york ,rapid ,transit ,railway4 ,he _h ! opportunity ( driv+ two p>allel tunnels "u ,murray ,hill only #ag ft4 ap>t4 ,! ea/]n tunnel 0 driv5 by ! drift me?od1 ! we/]n "o by ! head+ me?od4 ,aft] ! "w _h proce$$ = a few mon?s1 ,mr4 ,%al] /at$ t 9 8 case ! drift me?od 0 m conv5i5t4 ,he c\ld sp>e drill+ sev]al holes at ea* advance1 ?us obta9+ economy 9 "t1 labor & mat]ial )\t consid]+ ! advantage ( a simpl] transportation ( ! dbris4 ,he promis$ to publi% 8 results = ! b5efit ( ! pr(ession1 b1 un=tunately1 lo/ 8 life 9 an accid5t 9 ! tunnel be=e ! completion ( ! "w4 ,an advantage t ! drift me?od af=ds 9 long tunnels is1 t ! wat]1 :i* is usually f\nd 9 l>ge quantities "u high m\nta9s1 is easily collect$ 9 ! drift & convey$ to ! culv]t1 :ile 9 ! head+ me?od ! wat] f ! advance gall]y1 be=e be+ collect$ into ! culv]t built on ! floor ( ! tunnel1 mu/ pass ?r\gh all ! work+s4 ,?is may be a s]i\s inconv5i5ce :5 wat] is f\nd 9 l>ge quantities1 z1 = in/ance1 0 ! case 9 ! ,/4 ,go?>d tunnel1 :]e ! /ream am\nt$ to #eg gallons p] second4 ,,*apt] ,,xii4 ,,excavat+ ,,tunnels ,,?r\gh ,,s(t ,,gr\nd2 ,,g5]al ,,discussion2 ,,! ,,belgian ,,me?od4 ,,g5]al ,,discussion4 ,x may be set d[n z a g5]al tru? t ! excavation ( tunnels ?r\gh s(t gr\nd is ! mo/ difficult task :i* confronts ! tunnel eng9e]4 ,"u ! g5]al t]m ( s(t gr\nd1 h[ev]1 a great v>iety ( mat]ials is includ$1 beg9n+ ) /ratifi$ s(t rock & ! mo/ /able s&s & clays1 & end+ ) lam9at$ clay ( ! wor/ "*4 ,f ?is x is evid5t t c]ta9 k9ds ( s(t-gr\nd tunnel+ may be less difficult ?an ! tunnel+ ( rock1 & t o!r k9ds may pres5t almo/ insurm\ntable difficulties4 ,class+ bo? ! easy & ! difficult mat]ials toge!r1 h[ev]1 ! accuracy ( ! /atem5t fir/ made holds good 9 a g5]al way4 ,:atev] ! op9ion may be 9 reg>d to ?is po9t1 h[ev]1 !re is no *ance = dispute 9 ! /atem5t t ! difficulty ( tunnel+ ! s(t] & m trea*]\s clays1 peats1 & s&s is great] ?an t ( tunnel+ firm soils & rock2 & if we describe ! me?ods :i* are us$ successfully 9 tunnel+ v un/able mat]ials1 no difficulty ne$ be exp]i5c$ 9 modify+ !m to h&le /able mat]ials4 ,*>act]i/ics ( ,s(t-,gr\nd ,tunnel+4--,! pr9cipal *>act]i/ics :i* di/+ui% s(t-gr\nd tunnel+ are1 fir/1 t ! mat]ial is excavat$ )\t ! use ( explosives1 & second1 t ! excavation has to be /rutt$ practically z fa/ z x is complet$4 ,9 trea*]\s soils ! excavation also pres5ts o!r *>act]i/ic ph5om5a3 ,! mat]ial =m+ ! walls ( ! excavation t5ds to cave & slide4 ,?is t5d5cy may develop imm$iately ^u excavation1 or x may be ( sl[] gr[?1 due to wea!r+ & o!r natural causes4 ,9 ei!r case ! ro( ( ! excavations t5ds to fall1 ! sides t5d to cave inw>d & squeeze toge!r1 & ! bottom t5ds to bulge or swell upw>d4 ,9 mat]ials ( v un/able "* ^! movem5ts ex]t enorm\s pressures ^u ! timb]+ or /rutt+1 & 9 especially bad cases may de/roy & cru% ! /rutt+ completely4 ,outside ! tunnel ! surface ( ! gr\nd above s9ks = a consid]able di/ance on ea* side ( ! l9e ( ! tunnel4 ,me?ods ( ,s(t-,gr\nd ,tunnel+4--,!re are a v>iety ( me?ods ( tunnel+ ?r\gh s(t gr\nd4 ,"s ( ^!1 l ! quicks& me?od & ! %ield me?od1 diff] 9 "* entirely1 :ile 9 o!rs1 l ! ,belgian1 ,g]man1 ,engli%1 ,au/rian1 & ,italian me?ods1 ! diff]5ce consi/s simply 9 ! diff]5t ord] 9 :i* ! drifts & head+s are driv51 9 ! diff]5ce 9 ! numb] & size ( ^! advance gall]ies1 & 9 ! diff]5t =ms ( /rutt+ framework employ$4 ,9 ?is book ! %ield me?od is consid]$ individually2 b ! description ( ! ,belgian1 ,g]man1 ,engli%1 ,au/rian1 ,italian1 & quicks& me?ods are gr\p$ toge!r 9 ?is & ! ?ree succe$+ *apt]s to p]mit ( easy comp>ison4 ,,! ,,belgian ,,me?od ,,( ,,tunnel+ ,,?r\gh ,,s(t ,,gr\nd4 ,illu/ration3 ,,figs4 #fh & #fh;,a4--,diagrams ,%[+ ,sequ5ce ( ,excavations 9 ! ,belgian ,me?od4 ,! ,belgian me?od ( tunnel+ ?r\gh s(t gr\nd 0 fir/ employ$ 9 #ahbh 9 excavat+ ! ,*>l]oy tunnel ( ! ,brussels-,*>l]oy ,canal 9 ,belgium1 & x takes its "n f ! c\ntry 9 :i* x orig9at$4 ,! di/9ctive *>act]i/ic ( ! me?od is ! con/ruction ( ! ro( ar* be=e ! side walls & inv]t are built4 ,! excavation1 !re=e1 beg9s ) ! driv+ ( a top c5t] head+ :i* is enl>g$ until ! :ole ( ! section above ! spr++ l9es ( ! ar* is op5$4 ,v>i\s modifications ( ! me?od h be5 develop$1 & "s ( ! m important ( ^! w be describ$ f>!r on1 b we %all beg9 its consid]ation "h by describ+ fir/ ! orig9al & usual mode ( proc$ure4 ,excavation4--,fig4 #fh is ! excavation diagram ( ! ,belgian me?od ( tunnel+4 ,! excavation is begun by op5+ ! c5t] top head+ ,no4 #a1 :i* is c>ri$ ahead a great] or less di/ance1 dep5d+ ^u ! nature ( ! soil1 & is imm$iately /rutt$4 ,?is head+ is !n deep5$ by excavat+ "p ,no4 #b1 to a dep? correspond+ to ! spr++ l9es ( ! ro( ar*4 ,! next /ep is to remove ! two side sections ,no4 #c1 by attack+ !m at ! two fronts & at ! sides ) f\r gangs ( excavators4 ,! regul>ity & effici5cy ( ! mode ( proc$ure describ$ consi/ 9 adopt+ su* dim5sions = ^! sev]al p>ts ( ! section t ea* w be excavat$ at ! same rate ( spe$4 ,:5 ! upp] "p ( ! section has be5 excavat$ z describ$1 ! ro( ar* is built1 ) its feet support$ by ! unexcavat$ e>? bel[4 ,?is portion ( ! section is excavat$ by tak+ out fir/ ! c5tral tr5* ,no4 #d to ! dep? ( ! bottom ( ! tunnel1 & !n by remov+ ! two side p>ts ,no4 #e4 ,z ^! side p>ts ,no4 #e h to support ! ar*1 !y h to be excavat$ 9 su* a way z n to endang] x4 ,at int]vals along ! c5tral tr5* ,no4 #d1 transv]se or side tr5*es ab\t #b ft4 wide are excavat$ on bo? sides1 & /ruts are ins]t$ to support ! masonry previ\sly support$ by ! e>? :i* has be5 remov$4 ,! next /ep is to wid5 ^! side tr5*es1 & ins]t /ruts until all ( ! mat]ial 9 p>ts ,no4 #e is tak5 out4 ,:5 ! mat]ial p5etrat$ is firm en\gh to p]mit1 ! plan ( excavation illu/rat$ by ! diagram1 ,fig4 #fh;,a1 is sub/itut$ = ! m typical "o j describ$4 ,! only diff]5ce 9 ! two me?ods consi/s 9 ! plan ( excavat+ ! upp] "p ( ! pr(ile1 :i* 9 ! second me?od consi/s 9 driv+ fir/ ! c5t] top head+ ,no4 #a1 & !n 9 tak+ out ! rema9d] ( ! section above ! spr++ l9es ( ! ar* 9 "o op]ation1 :ile 9 ! fir/ me?od x is done 9 two op]ations4 ,! di/ance ahead ( ! masonry to :i* ! v>i\s p>ts c be driv5 v>ies f #aj ft4 to1 9 "s cases1 #ajj ft41 be+ v %ort 9 trea*]\s gr\nd1 & long] ! m /able ! mat]ial is4 ,/rutt+4--,! longitud9al me?od ( /rutt+1 ) ! pol+-bo>ds runn+ transv]sely ( ! tunnel1 is always employ$ 9 ! ,belgian me?od ( tunnel+4 ,9 driv+ ! fir/ c5t] top head+1 pairs ( v]tical po/s c>ry+ a transv]se cap-piece are erect$ at int]vals4 ,on ^! cap-pieces are c>ri$ two longitud9al b>s1 :i* 9 turn support ! saddle planks4 ,z fa/ z "p ,no4 #b1 ,fig4 #fh1 is excavat$1 ! v]tical po/s are replac$ by ! batt] po/s ,a & ,b1 ,fig4 #fi4 ,! excavation ( p>ts ,no4 #c is begun at ! top1 ! pol+-bo>ds a & b be+ ins]t$ z ! "w progresses4 ,to support ! out] ends ( ^! pol+-bo>ds1 ! longitud9als ,x & ,y are ins]t$ & support$ by ! batt] po/s ,c & ,d4 ,9 exactly ! same way ! pol+-bo>ds c & d1 ! longitud9als ,v & ,w1 & ! /ruts ,e & ,f1 are plac$ 9 position2 & ?is proc$ure is repeat$ until ! :ole top "p ( ! section is /rutt$1 z %[n by ,fig4 #fi1 ! cross /ruts x1 y1 z1 etc41 be+ ins]t$ to hold ! radial /ruts firmly 9 position4 ,! feet ( ! v>i\s radial props re/ on ! sill ,m ,n4 ,^! fan-l timb] /ructures are set up at int]vals ( f #c ft4 to #f ft41 dep5d+ ^u ! quality ( ! soil p5etrat$4 ,illu/ration3 ,,fig4 #fi4--,sket* ,%[+ ,radial ,ro( ,/rutt+1 ,belgian ,me?od4 ,illu/ration3 ,,fig4 #gj4--,sket* ,%[+ ,ro( ,ar* ,c5t]1 ,belgian ,me?od4 ,c5t]s4--,ei!r plank or truss$ c5t]s may be employ$ 9 lay+ ! ro( ar* 9 ! ,belgian me?od1 b ! =m ( c5t] commonly employ$ is a truss$ c5t] con/ruct$ z %[n by ,fig4 #gj4 ,x may be said to consi/ ( a k+-po/ truss c>ri$ on top ( a modifi$ =m ( que5-po/ truss4 ,! coll>-beam & ! tie-beam ( ! que5-po/ truss are spac$ ab\t #g ft4 ap>t1 & ! po/s !mselves are left f> en\gh ap>t to all[ ! passage ( workm5 & c>s betwe5 !m4 ,! tie beam ( ! k+-po/ truss is clamp$ to ! coll>-beam ( ! que5-po/ truss by iron b&s4 ,on ! raft]s ( ! two trusses are fa/5$ timb]s1 ) _! out] edges cut to ! curve ( ! ro( ar*4 ,^! c5t]s are set up midway betwe5 ! fan-l /rutt+ frames previ\sly describ$4 ,!y are usually built ( squ>e timb]s4 ,! tie beams are usually #f #f 941 & ! /ruts & po/s #d #d 94 timb]s4 ,! reason = giv+ ! l>g] sectional dim5sions to ! tie beams1 contr>y to ! usual practice 9 con/ruct+ c5t]s1 is t x has to s]ve z a sill = di/ribut+ ! pressure to ! f\ndation ( unexcavat$ soil :i* supports ! c5t]4 ,sometimes a sub-sill is us$ to support ! c5t] ^u ! soil2 & 9 any case w$ges are employ$ to c>ry x1 :i* c be remov$ = ! purpose ( /rik+ ! c5t]4 ,aft] ! ar* is complet$1 ! c5t]s may be remov$ imm$iately1 or may be left 9 position until ! masonry has ?or\ghly set4 ,9 ei!r case ! lead+ c5t] ov] :i* ! ar* masonry t]m9ates tempor>ily is left 9 position until ! next section ( ! ar* is built4 ,masonry4--,! masonry ( ! ro( ar*1 :i* is ! fir/ "p built1 is ( necessity begun at ! spr++ l9es1 & ! fir/ c\rse re/s on %ort l5g?s ( heavy planks4 ,^! planks1 besides giv+ an ev5 surface ^u :i* to beg9 ! masonry1 are ess5tial 9 furni%+ a be>+ to ! /ruts ins]t$ to support ! ar* :ile ! e>? bel[ !m1 "p ,no4 #e1 ,fig4 #fh1 is be+ excavat$4 ,z ! ar* masonry progresses f ! spr++ l9es upw>d1 ! radial po/s ( ! /rutt+ are remov$1 & replac$ by %ort /ruts re/+ on ! lagg+ ( ! c5t]s1 :i* support ! cr[n b>s or longitud9als until ! masonry is 9 place1 :5 !y & ! pol+-bo>ds are remov$1 & ! space betwe5 ! ar* masonry & walls ( ! excavation is fill$ ) /one or well-ramm$ e>?4 ,consid]+ n[ ! side wall masonry1 x w be rememb]$ t 9 excavat+ ! "p ,no4 #e1 ,fig4 #fh1 ( ! section1 frequ5t side tr5*es 7 excavat$1 & /ruts ins]t$ to take ! weight ( ! masonry4 ,^! /ruts are ins]t$ on a batt]1 ) _! feet ne> ! c5t] ( ! tunnel floor1 s t ! side wall masonry may be c>ri$ up beh9d !m to a height z ne> z possible to ! spr++ l9es ( ! ar*4 ,:5 ?is is done ! /ruts are remov$1 & ! space rema9+ betwe5 ! top ( ! p>tly f9i%$ side wall & ! ar* is fill$ 94 ,?is leaves ! ar* support$ by alt]nate l5g?s or pill>s ( unexcavat$ e>? & complet$ side wall4 ,! next /ep is to remove ! rema9+ sections ( e>? betwe5 ! sections ( side wall1 & fill 9 ! space ) masonry4 ,fig4 #ga is a cross-section1 %[+ ! masonry complet$ = "o-half & ! incl9$ props 9 position = ! o!r half2 & ,fig4 #gb is a longitud9al section %[+ ! pill>s ( unexcavat$ e>? betwe5 ! consecutive sets ( incl9$ /ruts & sev]al o!r details ( ! l9+1 /rutt+1 & excavat+ "w4 ,illu/ration3 ,,fig4 #ga4--,sket* ,%[+ ,me?od ( ,und]p9n+ ,ro( ,ar* ) ! ,side ,wall ,masonry4 ,illu/ration3 ,,fig4 #gb4--,longitud9al ,section ,%[+ ,con/ruction by ! ,belgian ,me?od4 ,! inv]t masonry is built aft] ! side walls are complet$4 ,?is is reg>d$ z a defect ( ?is me?od ( tunnel+1 s9ce ! lat]al pressures may squeeze ! side walls toge!r & di/ort ! ar* be=e ! inv]t is 9 place to brace !m ap>t4 ,to prev5t z mu* z possible ! di/ortion ( ! ar* aft] ! c5t]s are remov$1 x is consid]$ good practice to %ore ! masonry ) horizontal beams hav+ _! ends abutt+ aga9/ plank1 z %[n by ,fig4 #ga4 ,^! horizontal beams %\ld be plac$ at close int]vals1 & be support$ at int]m$iate po9ts by v]tical po/s1 z %[n by ! illu/ration4 ,s9ce ! ro( ar* re/s are = "s "t support$ directly by ! unexcavat$ e>? bel[1 settlem5t is liable1 p>ticul>ly 9 work+ ?r\gh s(t gr\nd4 ,?is fact may n be v important s long z ! settlem5t is uni=m1 & is n en\gh to encroa* on ! space necess>y = ! safe passage ( travel4 ,to prev5t ! latt] possibility ! c5t]s are plac$ f #i ins4 to #ae ins4 high] ?an _! true positions1 dep5d+ ^u ! nature ( ! soil1 s t consid]able settlem5t is possible )\t any dang] ( ! necess>y cross-section be+ infr+$ ^u4 ,9 conclusion x may be not$ t ! l9+ may be con/ruct$ 9 a s]ies ( consecutive r+s1 or z a s+le cyl9drical mass4 ,haul+4--,s9ce 9 ?is me?od ( tunnel+ ! upp] "p ( ! section is excavat$ & l9$ be=e ! excavation ( ! l[] "p is begun1 ! upp] portion is always m advanc$ ?an ! l[]4 ,to c>ry away ! e>? excavat$ at ! front1 !re=e1 an elevation has to be surm\nt$2 & ?is is usually done by con/ruct+ an incl9$ plane ris+ f ! floor ( ! tunnel to ! floor ( ! head+1 z %[n by ,fig4 #gb4 ,?is incl9$ plane has1 ( c\rse1 to be mov$ ahead z ! "w advances1 & to p]mit ( ?is movem5t ) z little int]ruption ( ! o!r "w z possible1 two planes are employ$4 ,"o is erect$ at ! "r-h& side ( ! section1 & s]ves to c>ry ! traffic :ile ! left-h& side ( ! l[] section is be+ remov$ "s di/ance ahead & ! o!r plane is be+ erect$4 ,! incl9ation giv5 to ^! planes dep5ds ^u ! size ( ! loads to be haul$1 b !y %\ld always h z slight a grade z practicable4 ,n>r[-gauge tracks are laid on ^! planes & along ! floor ( ! upp] "p ( ! section pass+ ?r\gh ! c5t] op5+ m5tion$ be=e z be+ left 9 ! c5t]s & /rutt+4 ,9 excavat+ ! top c5t] head+ !re is1 ( c\rse1 ano!r rise to its floor f ! floor ( ! upp] "p ( ! section4 ,:]e1 z is usually ! case 9 s(t soils1 ?is top head+ is n driv5 v f> 9 advance1 ! e>? f ! front is usually convey$ to ! re> 9 :eelb>r[s1 & dump$ into ! c>s /&+ on ! tracks bel[4 ,9 firm soils1 :]e ! head+ is driv5 too f> 9 advance to make ?is me?od ( conveyance adequate1 tracks are also laid on ! floor ( ! head+1 & an incl9$ plane is built connect+ x ) ! tracks on ! next level bel[4 ,9 place ( ^! incl9$ planes1 & also 9 place ( ^? betwe5 ! floor ( ! tunnel & ! level above1 "s =m ( hoi/+ device is sometimes employ$ to lift ! c>s f "o level to ! o!r4 ,!re are "s advantages to ?is me?od 9 po9t ( economy1 b ! hoi/+-ma*9es are n easily work$ 9 ! d>kness1 & accid5ts are likely to occur4 ,illu/ration3 ,,fig4 #gc4--;,diagram ,%[+ ,sequ5ce ( ,excavation 9 ,modifi$ ,belgian ,me?od4 ,9 ! advanc$ top head+ & 9 ! upp] "p ( ! section n>r[-gauge tracks are necess>ily employ$1 & ^! may be cont9u$ along ! floor ( ! f9i%$ section1 or ! p]man5t broad-gauge railway tracks may be laid z fa/ z ! full section is complet$4 ,9 ! =m] case ! p]man5t tracks are n laid until ! entire tunnel is practically complet$2 & 9 ! latt] case1 unless a ?ird rail is laid1 ! loads h to be trans%ipp$ f ! broad- to ! n>r[-gauge tracks or vice v]sa4 ,x is ! m g5]al practice to use a ?ird rail r ?an to trans%ip e load4 ,modifications4--,consid]+ ! ext5t to :i* ! ,belgian me?od ( tunnel+ has be5 employ$1 x is n surpris+ t _m modifications ( ! /&>d mode ( proc$ure h be5 develop$4 ,! modification :i* diff]s mo/ f ! /&>d =m is1 p]haps1 t adopt$ 9 excavat+ ! ,roosebeck tunnel 9 ,g]many4 ,?is me?od pres]ves ! pr9cipal *>act]i/ic ( ! ,belgian me?od1 :i* is ! con/ruction ( ! upp] "p ( ! section fir/2 b in/ead ( build+ ! side walls f ! bottom upw>d1 !y are built 9 small sections f ! top d[nw>d4 ,! excavation beg9s by driv+ ! c5t] top head+ ,no4 #a1 ,fig4 #gc1 ^: floor is at ! level ( ! spr++ l9es ( ! ro( ar*1 & !n ! two side p>ts ,no4 #b are excavat$1 op5+ up ! entire upp] portion ( ! section 9 :i* ! ro( ar* is built1 z 9 ! regul> ,belgian me?od4 ,! next /ep is to excavate "p ,no4 #c1 %or+ up ! ar* at frequ5t int]vals4 ,betwe5 ^! sets ( %or+ ! side walls are built1 re/+ on planks on ! floor ( "p ,no4 #c1 & !n ! sets ( %ores are remov$ & replac$ by masonry4 ,next "p ,no4 #d is excavat$1 %or$1 & fill$ ) masonry z 0 "p ,no4 #c4 ,9 exactly ! same way p>ts #e1 #f1 #g1 & #h are con/ruct$ 9 ! ord] numb]$4 ,to prev5t ! di/ortion ( ! ar* dur+ ! side-wall con/ruction x is brac$ by horizontal /ruts1 z indicat$ above 9 ,fig4 #ga4 ,advantages4--,! advantages ( ! ,belgian me?od ( tunnel+ may be summ>iz$ z foll[s3 7#a7 ,! excavation progresses simultane\sly at sev]al po9ts )\t ! diff]5t gangs ( excavators int]f]+ ) ea* o!r1 ?us secur+ rapidity & effici5cy ( "w2 7#b7 ! excavation is done by driv+ a numb] ( drifts or p>ts ( small section1 :i* are imm$iately /rutt$1 ?us caus+ ! m9imum di/urbance ( ! surr\nd+ mat]ial2 7#c7 ! ro( ( ! tunnel1 :i* is ! "p ( ! l9+ expos$ to ! greate/ pressures1 is built fir/4 ,illu/ration3 ,,fig4 #gd4--,sket* ,%[+ ,failure ( ,ro( ,ar* by ,op5+ at ,cr[n4 ,disadvantages4--,! disadvantages ( ! ,belgian me?od ( tunnel+ may be summ>iz$ z foll[s3 7#a7 ,! ro( ar* :i* re/s at fir/ on compressible soil is liable to s9k2 7#b7 be=e ! inv]t is built !re is dang] ( ! ar* & side walls be+ di/ort$ or slid+ "u ! lat]al pressures2 7#c7 ! masonry ( ! side walls has to be und]p9n$ to ! ar* masonry4 ,accid5ts & ,repairs4--,"o ( ! mo/ frequ5t accid5ts 9 ! ,belgian me?od ( tunnel+ is ! s9k+ ( ! ro( ar* ow+ to its un/able f\ndation on ! unexcavat$ soil ( ! l[] portion ( ! section4 ,! am\nt ( settlem5t may v>y f a few in*es 9 firm soil to ov] #b ft4 9 loose soils4 ,to c\nt]act ! effect ( ?is settlem5t x is ! g5]al practice to build ! ar* "s in*es high] ?an its normal position4 ,:5 ! settlem5t is great en\gh to infr+e s]i\sly ^u ! tunnel section1 repairs h to be made2 & ! only way ( accompli%+ !m is to demoli% ! ar* & rebuild x f ! side walls4 ,x is usually consid]$ be/ n to demoli% ! ar* until ! inv]t has be5 plac$1 s t no fur!r di/urbance is likely to occur once ! l9+ is complet$ anew4 ,! rotation ( ! ar* ab\t its key/one1 or ! op5+ ( ! ar* at ! cr[n1 by ! squeez+ inw>d ( ! haun*es by ! lat]al pressures1 is ano!r *>act]i/ic accid5t4 ,fig4 #gd %[s ! nature ( ! di/ortion produc$2 ! segm5ts ( ! ar* move t[>d ea* o!r by revolv+ on ! intradosal edges ( ! key/one1 :i* are brok5 away & cru%$ toge!r ) ! op]ation1 :ile ! extradosal edges are op5$4 ,x is to prev5t ?is occurr5ce t ! horizontal /ruts %[n 9 ,fig4 #ga are employ$4 ,! mann] ( repair+ ?is accid5t diff]s1 dep5d+ ^u ! ext5t ( ! injury4 ,:5 ! intradosal edges ( ! key/one are b slightly cru%$1 ! repair+ is done z direct$ by ,fig4 #ge4 ,:5 ! key/one is completely cru%$1 h[ev]1 ! indications are t ! mat]ial ( ! key/one1 usually brick1 is n /rong en\gh to resi/ ! pressures com+ ^u x1 & x is advisable to sub/itute a /rong] mat]ial 9 ! repairs1 & a /one key/one is con/ruct$ z %[n by ,fig4 #ge4 ,! middle /one ( ?is key/one ext5ds ?r\gh ! dep? ( ! ar* r+1 & ! two side /ones only half-way ?r\gh1 _! purpose be+ m]ely to resi/ ! cru%+ =ces :i* are greate/ at ! intrados4 ,sometimes1 :5 ! pressures are unsymmetrical1 ! ar* r+ breaks at ! haun*es z well z ! cr[n1 z %[n by ,fig4 #ge1 :i* also indicates ! mode ( repair+4 ,?is consi/s 9 demoli%+ ! orig9al ar*1 & rebuild+ x ) /one v\ssoirs ins]t$ 9 place ( ! brick 9 :i* ! rupture occurr$4 ,illu/ration3 ,,fig4 #ge4--,sket*es ,%[+ ,me?ods ( ,repair+ ,ro( ,ar* ,failures4 ,,*apt] ,,xiii4 ,,! ,,g]man ,,me?od--,,excavat+ ,,tunnels ,,?r\gh ,,s(t ,,gr\nd 7,cont9u$72 ,,baltimore ,,belt ,,l9e ,,tunnel4 ,! ,g]man me?od ( tunnel+ 0 fir/ us$ 9 #ahjc 9 con/ruct+ ! ,/4 ,qu5t9 ,canal4 ,9 #ahcg ! ,knigsdorf tunnel ( ! ,cologne & ,aix la ,*apelle ,r4,r4 0 excavat$ by ! same me?od4 ,! success ( ! me?od 9 ^! two difficult pieces ( s(t-gr\nd tunnel+ l$ to its ext5sive adoption ?r\gh\t ,g]many1 & = ?is reason x gradually came to be designat$ z ! ,g]man me?od4 ,briefly expla9$ ! me?od consi/s 9 excavat+ fir/ an annul> gall]y 9 :i* ! side walls & ro( ar* are built complete be=e tak+ out ! c5t] core & build+ ! inv]t4 ,illu/ration3 ,,fig4 #gf4--;,diagrams ,%[+ ,sequ5ce ( ,excavation 9 ,g]man ,me?od ( ,tunnel+4 ,excavation4--,! excavation ( tunnels by ! ,g]man me?od is begun ei!r by driv+ two bottom side drifts or by driv+ a c5t] top head+4 ,fig4 #gf %[s ! mode ( proc$ure :5 bottom side drifts are us$ to />t ! "w4 ,! two side drifts ,no4 #a are made f #g ft4 to #h ft4 wide1 & ab\t "o-?ird ! total height ( ! full section2 ! wid? ( ea* head+ has to be suffici5t = ! con/ruction ( ! masonry & /rutt+1 & = ! passage ( n>r[ spoil c>s alongside !m4 ,^! drifts are increas$ 9 height to ! spr++ l9e ( ! ar* by tak+ out ! two drifts ,no4 #b4 ,next ! top c5t] head+ ,no4 #c is driv51 & f9ally ! two haun* head+s ,no4 #d are excavat$4 ,! c5t] core ,no4 #e is utiliz$ to support ! /rutt+ until ! side walls & ro( ar* are complet$1 :5 x is brok5 d[n & remov$4 ,9 case ( v loose mat]ial1 :]e ! fir/ side drifts _c be c>ri$ z high z "o-?ird ! height ( ! section1 x is ! common practice to make !m ab\t "o-f\r? ! height1 & to take out ! side portions ( ! annul> gall]y 9 ?ree p>ts1 z %[n by ,fig4 #gf4 ,illu/ration3 ,,fig4 #gg4--;,diagram ,%[+ ,sequ5ce ( ,excavations 9 ,wat] ,be>+ ,mat]ial1 ,g]man ,me?od4 ,! top c5t] head+ plan ( comm5c+ ! excavation is usually employ$ 9 firm mat]ials or :5 a ve9 ( wat] is enc\nt]$ 9 ! upp] "p ( ! section4 ,9 ! latt] cont+5cy a small bottom drift ,a1 ,fig4 #gg1 is fir/ driv5 to s]ve z a dra92 b 9 any case ! excavation prop] ( ! tunnel consi/s 9 fir/ driv+ ! c5t] top head+ ,no4 #a1 & !n by work+ bo? ways along ! pr(ile p>ts1 ,nos4 #b1 #c1 #d1 & #e are remov$4 ,"p ,no4 #f is left to support ! /rutt+ until ! side walls & ro( ar* are built1 :5 x is also excavat$4 ,/rutt+4--,:5 ! excavation is begun by bottom side drifts ^! drifts are /rutt$ by erect+ v]tical po/s close aga9/ ! sides ( ! drift & plac+ a cap-piece transv]sely across ! ro( ( ! drift4 ,! side po/s are usually support$ by sills plac$ across ! bottom ( ! drift4 ,^! frameworks ( po/s1 cap1 & sill are erect$ at %ort int]vals1 & ! ro(1 &1 if necess>y1 ! sides ( ! drift betwe5 !m1 are su/a9$ by means ( longitud9al pol+-bo>ds ext5d+ f "o frame to ! next4 ,! cap-pieces ( ! /rutt+ = ! bottom drifts s]ve z sills = ! exactly simil> /rutt+ ( ! head+ next above4 ,to support ! additional weight1 & to all[ ! con/ruction ( ! side walls1 ! /rutt+ ( ! bottom drifts is /r5g!n$ by ins]t+ an int]m$iate po/ betwe5 ! orig9al side po/s ( ea* frame4 ,^! int]m$iate po/s are n ins]t$ at ! c5t] ( ! frames or b5ts1 b close to ! wall masonry l9e z %[n by ,fig4 #gh4 ,?is ecc5tric position ( ! po/ avoids any int]f]5ce ) ! haul+1 & also all[s ! removal ( ! adjac5t side po/ :5 ! masonry is con/ruct$4 ,illu/ration3 ,,fig4 #gh4--,sket* ,%[+ ,"w ( ,excavat+ & ,timb]+ ,drifts & ,head+s4 ,illu/ration3 ,,fig4 #gi4--,sket* ,%[+ ,me?od ( ,ro( ,/rutt+4 ,two me?ods ( /rutt+ ! s(fit ( ! excavation are employ$1 "o be+ a modification ( ! longitud9al sy/em employ$ 9 ! ,engli% me?od ( tunnel+ describ$ 9 a succe$+ *apt]1 & ! o!r a modification ( ! ,belgian sy/em previ\sly describ$4 ,fig4 #gi %[s ! me?od ( employ+ ! radial /rutt+ ( ! ,belgian sy/em4 ,at ! beg9n+ ! c5t] top head+ is /rutt$ ) rectangul> b5ts su* z are employ$ = /rutt+ ! drifts4 ,z ?is head+ is enl>g$ by tak+ out ! haun* sections1 radial po/s are ins]t$1 z %[n by ,fig4 #gi1 :i* also indicates ! me?od ( /rutt+ ! side tr5*es :5 ! excavation is c>ri$ d[nw>d f ! c5t] top head+ in/ead ( upw>d f bottom side drifts4 ,masonry4--,:atev] plan ( excavation or /rutt+ is employ$1 ! con/ruction ( ! masonry l9+ 9 ! ,g]man me?od ( tunnel+ beg9s at ! f\ndations ( ! side walls & is c>ri$ upw>d to ! ro( ar*4 ,! inv]t1 if "o is requir$1 is built aft] ! c5t] core ( e>? is remov$4 ,c5t]+4--,tunnel c5t]s are g5]ally employ$ 9 ! ,g]man me?od ( tunnel+1 a common con/ruction be+ %[n by ,fig4 #hj4 ,x is ess5tially a que5-po/ truss1 ! tie beam ( :i* re/s on a transv]se sill z %[n by ! illu/ration4 ,! transv]se sill is support$ along its c5tral portion by ! unexcavat$ c5t] core ( e>?1 & at its ends ei!r directly on ! v]tical po/s or on longitud9al beams re/+ on ^! po/s4 ,! diagonal memb]s ( ! que5-po/ truss =m ! bottom *ords ( small k+-po/ trusses :i* are employ$ to build out ! ext]ior memb] ( ! c5t] to a clos] approximation to ! curve ( ! ar*4 ,illu/ration3 ,,fig4 #hj4--,sket* ,%[+ ,ro( ,ar* ,c5t]s & ,ar* ,con/ruction4 ,haul+4--,:5 ! bottom side drift plan ( excavation is employ$1 ! spoil f ! front ( ! drift is remov$ 9 n>r[-gauge c>s runn+ on a track laid z close z practicable to ! c5t] core4 ,^! same c>s are also employ$ to take ! spoil f ! drifts above1 ?r\gh holes left 9 ! ceil+ /rutt+ ( ! bottom drifts4 ,! spoil f ! s(fit sections may be remov$ by ! same c> l9es us$ 9 excavat+ ! drifts1 or a n>r[-gauge track may be laid on ! top ( ! c5t] core = ?is special purpose4 ,9 ! latt] case ! s(fit tracks are usually connect$ by means ( incl9$ planes ) ! tracks on ! bottoms ( ! side drifts4 ,g5]ally1 h[ev]1 ! sep>ate s(fit c> l9e is n us$ unless ! mat]ial is ( su* a firm "* t ! head+s & drifts c be c>ri$ a great di/ance ahead ( ! masonry "w4 ,) ! c5t] top head+ plan ( beg9n+ ! excavation1 ! c> track has1 ( c\rse1 to be laid on ! top ( ! c5t] core4 ,! c5t] core itself is remov$ by means ( c> tracks along ! floor ( ! complet$ tunnel4 ,advantages & ,disadvantages4--,l ! ,belgian me?od ( tunnel+1 ! ,g]man me?od has its advantages & disadvantages4 ,s9ce ! excavation consi/s at fir/ ( a n>r[ annul> gall]y only1 ! equilibrium ( ! e>? is n greatly di/urb$1 & ! /rutt+ does n ne$ to be s heavy z 9 me?ods :]e ! op5+ is mu* l>g]4 ,! undi/urb$ c5t] core also furni%es an excell5t support = ! /rutt+1 & = ! c5t]s ^u :i* ! ro( ar*es are built4 ,ano!r important advantage ( ! me?od is t ! con/ruction ( ! masonry l9+ is begun logically at ! bottom1 & progresses upw>d1 & a m homog5e\s & /able con/ruction is possible4 ,! great disadvantage ( ! me?od is ! small space 9 :i* ! haul+ has to be done4 ,! spoil c>s practically fill ! n>r[ drifts 9 pass+ to & f ! front1 & int]f]e greatly ) ! "w ( ! c>p5t]s & masons4 ,ano!r objection to ! me?od is t ! inv]t is ! v la/ portion ( ! l9+ to be built4 ,?is may n be a s]i\s objection 9 reasonably compact & /able mat]ials1 b 9 v loose soils !re is always ! dang] ( ! side walls be+ squeez$ toge!r be=e ! inv]t masonry is 9 position to hold !m ap>t4 ,altoge!r ! difficulties are ( a "* :i* t5d to increase ! exp5se ( ! me?od1 & ?is is ! reason :y to-day x is seldom us$ ev5 9 ! c\ntry :]e x 0 fir/ develop$1 & = "s "t ext5sively employ$4 ,= repair+ accid5ts1 su* z ! cav+ 9 ( complet$ tunnels1 ! ,g]man me?od ( tunnel+ is frequ5tly us$1 because ( ! ease ) :i* ! timb]+ is accompli%$4 ,9 su* cases ! co/ ( ! me?od us$ cuts a small figure1 s long z x is safe & exp$iti\s4 ,,baltimore ,,belt ,,l9e ,,tunnel4 ,9 ! la/ few ye>s a modification ( ! ,g]man me?od 0 us$ 9 ?is c\ntry = ! con/ruction ( sev]al railroad tunnels4 ,! modification consi/s 9 excavat+ ! two-side drifts up to ! spr++ l9e ( ! ar* ( ! propos$ tunnel4 ,!n a c5tral head+1 :i* is aft]w>d enl>g$ to ! :ole section ( ! tunnel1 is excavat$ close to ! cr[n4 ,at ! same "t ! masonry is con/ruct$ f ! f\ndation up 9 ! side drifts4 ,f ! floor ( ! upp] section already excavat$ & /rutt$1 ! top ( ! masonry ( ! drifts is rea*$ by means ( small side cuts2 ?us ! l9+ is made cont9u\s up to ! key/one4 ,! c5tral nucleus or b5* is remov$ aft] ! tunnel has be5 l9$4 ,! mo/ important tunnel excavat$ by ?is me?od 0 ! ,baltimore ,belt ,l9e tunnel describ$ z foll[s3 ,! ,baltimore ,belt ,ry4 ,co4 0 organiz$ 9 #ahij by (ficials ( ! ,baltimore ,ohio1 & ,we/]n ,m>yl& railways1 & ,baltimore ,capitali/s1 to build #g miles ( d\ble track railway1 mo/ly )9 ! city limits ( ,baltimore4 ,?is railway 0 p>tly op5 cut & embankm5t1 & p>tly tunnel1 & its object 0 to af=d ! companies nam$ facilities = rea*+ ! c5t] ( ! city ) _! pass5g]s & freight4 ,to c>ry out ! "w ! ,m>yl& ,con/ruction ,co4 0 organiz$ by ! p>ties int]e/$1 & 9 ,septemb]1 #ahij1 ?is company let ! contract = con/ruction to ,ryan ,mc,donald ( ,baltimore1 ,md4 ,! *ief difficulties ( ! "w c5t]$ 9 ! con/ruction ( ! ,h[>d-/reet tunnel1 #hcej ft4 long1 runn+ und]nea? ! pr9cipal bus9ess section ( ! city4 ,mat]ial ,p5etrat$4--,! soil p5etrat$ by ! tunnel 0 ( almo/ all k9ds & consi/5cies1 b 0 *iefly s& ( v>y+ degrees ( f95ess p5etrat$ by seams ( loam1 clay1 & gravel4 ,"s ( ! clay 0 s h>d & t\gh t x c\ld n be remov$ except by bla/+4 ,rock 0 also f\nd 9 a few places4 ,= ! mo/ "p1 h[ev]1 ! "w 0 ?r\gh s(t gr\nd1 furni%+ m or less wat]1 :i* necessitat$ unusual precautions to avoid ! settl+ ( ! /reet1 & consequ5t damage to ! build+s along ! l9e4 ,a l>ge quantity ( wat] 0 enc\nt]$4 ,g5]ally ?is wat] c\ld be remov$ by dra9age & pumps1 & ! e>? be prev5t$ f wa%+ 9 by pack+ ! space betwe5 ! timb]+ ) hay or o!r mat]ials4 ,at po9ts :]e ! infl[ 0 greate/1 & ! e>? 0 wa%$ 9 despite ! hay pack+1 ! me?od 0 adopt$ ( driv+ #f-;94 p]=at$ pipes into ! sides ( ! excavation1 & =c+ cem5t gr\t ?r\gh !m into ! soil to solidify x4 ,^! pipes p5etrat$ ! gr\nd ab\t #aj ft41 & ! me?od prov$ v effici5t 9 prev5t+ ! infl[ ( wat]4 ,excavation4--,! excavation 0 c>ri$ out accord+ to ! ,g]man me?od ( tunnel+4 ,bottom side drifts 7 fir/ driv51 & !n height5$ to ! spr++ l9e ( ! ro( ar*4 ,next a c5t] top head+ 0 driv51 & ! haun* sections tak5 out4 ,! object ( beg9n+ ! excavations by bottom side drifts1 0 to dra9 ! soil ( ! upp] "p ( ! section4 ,! c5t] core 0 remov$ aft] ! side walls & ro( ar* 7 complet$1 its removal be+ kept f #ej ft4 to #ge ft4 to ! re> ( ! advanc$ head+4 ,! dim5sions ( ! side drifts prop] 7 ab\t #h #h ft41 b !y 7 (t5 c>ri$ d[n mu* bel[ ! floor level to secure a solid f\ndation b$ = ! side walls4 ,/rutt+4--,! side drifts 7 /rutt$ by means ( frames compos$ ( two batt] po/s re/+ on bo>ds1 & hav+ a cap-piece ext5d+ transv]sely across ! ro( ( ! drift4 ,^! frames 7 spac$ ab\t #d ft4 ap>t4 ,! excavation 0 advanc$ 9 ! usual way by driv+ pol+-bo>ds at ! top & sides1 ) a slight outw>d & upw>d incl9ation1 s t ! next frame c\ld be easily ins]t$ leav+ space en\gh betwe5 x & ! %eet+ to p]mit ! next set ( pol+-bo>ds to be ins]t$4 ,^! pol+-bo>ds 7 driv5 z close toge!r z practicable s z to prev5t z mu* z possible ! infl[ ( wat] & e>?4 ,illu/ration3 ,,fig4 #ha4--,sket* ,%[+ ,me?od ( ,excavat+ & ,/rutt+ ,baltimore ,belt ,l9e ,tunnel4 ,! c5t] top head+ 0 /rutt$ 9 ! same mann] z 7 ! side drifts4 ,! arrangem5t ( ! /rutt+ employ$ 9 enl>g+ ! c5t] top head+ is %[n cle>ly by ,fig4 #ha1 :i* also %[s ! mann] ( /rutt+ ! side drifts & face ( ! excavation1 & ( build+ ! masonry4 ,c5t]s4--,bo? wood & iron c5t]s 7 employ$ 9 build+ ! ro( ar*4 ,! timb] c5t]+ 0 con/ruct$ ( squ>e timb]s1 z %[n by ,fig4 #hb4 ,?is con/ruction ( ! iron c5t]s is %[n by ,fig4 #hc4 ,ea* ( ! iron c5t]s consi/$ ( two #f #f 94 angles butt$ toge!r1 & b5t into ! =m ( an ar* rib4 ,six ( ^! ribs 7 set up #d ft4 ap>t4 ,!y 7 made ( two half ribs butt$ toge!r at ! cr[n1 & 7 held erect & ! prop] di/ance ap>t by spac+ rods4 ,! re>mo/ rib 0 held fa/ to ! complet$ ar* masonry1 & 9 turn support$ ! =w>d ribs :ile ! lagg+ 0 be+ plac$4 ,illu/ration3 ,,fig4 #hb4--,ro( ,ar* ,con/ruction ) ,timb] ,c5t]s1 ,baltimore ,belt ,l9e ,tunnel4 ,masonry4--,! side walls ( ! l9+ 7 built fir/ 9 ! bottom side drifts1 z %[n by ,fig4 #ha4 ,!y 7 g5]ally plac$ on a f\ndation ( concrete1 f #a ft4 to #b ft4 ?ick4 ,z a rule ! side walls 7 n built m ?an #bj ft4 9 advance ( ! ar*1 b occasionally ?is di/ance 0 increas$ to z mu* z #ij ft4 ,! ro( ar* consi/$ ord9>ily ( five r+s ( brick1 b at "s places 9 especially un/able soil eight r+s ( brick 7 employ$4 ,! ar* 0 built 9 conc5tric sections ab\t #ah ft4 9 l5g?4 ,all ! timb] ( ! /rutt+ above ! ar* & outside ( ! side walls 0 left 9 place1 & ! voids 7 fill$ ) rubble masonry laid 9 cem5t mort>4 ,x requir$ ab\t #abe mason h\rs to build an #ah-;ft4 ar* section4 ,figs4 #hb & #hc %[ v>i\s details ( ! masonry ar* "w4 ,illu/ration3 ,,fig4 #hc4--,ro( ,ar* ,con/ruction ) ,iron ,c5t]s1 ,baltimore ,belt ,l9e ,tunnel4 ,ow+ to ! v un/able "* ( ! soil1 consid]able difficulty 0 exp]i5c$ 9 build+ ! masonry inv]t4 ,! process adopt$ 0 z foll[s3 ,two p>allel #ab #ab 94 timb]s 7 fir/ plac$ transv]sely across ! tunnel1 abutt+ aga9/ longitud9al timb]s or w$ges re/+ aga9/ ! side walls4 ,%ort %eet piles 7 !n driv5 into ! tunnel bottom outside ( ^! timb]s1 =m+ an inclosure simil> to a c(f]dam1 f :i* ! e>? c\ld be excavat$ )\t di/urb+ ! surr\nd+ gr\nd4 ,! e>? be+ excavat$1 a lay] ( concrete #h ins4 ?ick 0 plac$1 & ! brick masonry inv]t con/ruct$ on x4 ,9 less /able gr\nd ea* ( ! above describ$ c(f]dams 0 subdivid$ by transv]se timb]s & %eet pil+ into ?ree small] c(f]dams4 ,"h ! masonry ( ! middle section 0 fir/ con/ruct$1 & !n ! side sections built4 ,:]e ! gr\nd 0 wor/1 /ill m c>e 0 necess>y1 & ! bottom _h to be cov]$ ) a %eet+ ( #a-;94 plank held d[n by /ruts abutt+ aga9/ ! l>ge transv]se timb]s4 ,! inv]t masonry 0 con/ruct$ on ?is %eet+4 ,refuge ni*es #i ft4 high1 #c ft4 wide1 & #ae ins4 deep 7 built 9 ! side walls4 ,accid5ts4--,9 ?is tunnel1 ow+ to ! quick /rik+ ( ! c5t]s1 x 0 f\nd t ! masonry l9+ flatt5$ at ! cr[n & bulg$ at ! sides4 ,?is 0 attribut$ to ! insuffici5t "t all[$ = ! mort> to set 9 ! rubble fill+4 ,e>? pack+ 0 tri$1 b gave /ill worse results4 ,f9ally dry rubble fill+ 0 adopt$1 ) satisfactory results4 ,!re 0 necess>ily "s s9k+ ( ! surface4 ,?is result$ p>tly f ! necessity ( *ang+ & remov+ ( ! timb]s1 & f ! compression & spr++ ( ! timb]s "u ! great pressures4 ,! cr[n ( ! ar* also settl$ f #b ins4 to #f ins41 due to ! compression ( ! mort> 9 ! jo9ts4 ,! maximum s9k+ ( ! surface ( ! /reet ov] ! tunnel 0 ab\t #ah ins42 x usually ran f #a to #ab ins4 ,"s damage 0 done to ! wat] & gas ma9s4 ,?is damage 0 n usually s]i\s1 b x ( c\rse necessitat$ imm$iate repairs1 & 9 "s in/ances x 0 f\nd be/ to recon/ruct ! ma9s = "s di/ance4 ,at "o po9t along ! tunnel :]e v trea*]\s mat]ial 0 f\nd1 ! surface settlem5t caus$ ! collapse ( an adjac5t build+1 & necessitat$ its recon/ruction4 ,,*apt] ,,xiv4 ,,! ,,full ,,section ,,me?od ,,( ,,tunnel+3 ,,engli% ,,me?od2 ,,am]ican ,,me?od2 ,,au/rian ,,me?od4 ,,engli% ,,me?od4 ,! ,engli% me?od ( tunnel+ ?r\gh s(t gr\nd1 z its "n implies1 orig9at$ 9 ,engl&1 :]e1 ow+ to ! g5]al preval5ce ( comp>atively firm *alks1 clays1 %ales1 & s&/ones1 x has ga9$ unusual popul>ity4 ,! di/9ctive *>act]i/ics ( ! me?od are ! excavation ( ! full section ( ! tunnel at once1 ! use ( longitud9al /rutt+1 & ! alt]nate execution ( ! masonry "w & excavation4 ,9 ,am]ica ! me?od is g5]ally designat$ z ! longitud9al b> me?od1 ow+ to ! mode ( /rutt+1 :i* has ga9$ p>ticul> favor 9 ,am]ica1 & is commonly employ$ "h ev5 :5 ! mode ( excavation is di/9ctively ,g]man or ,belgian 9 o!r respects4 ,illu/ration3 ,,fig4 #hd4--;,diagram ,%[+ ,sequ5ce ( ,excavation 9 ,engli% ,me?od ( ,tunnel+4 ,excavation4--,al?\gh1 z /at$ above1 ! di/9ctive *>act]i/ic ( ! ,engli% me?od is ! excavation ( ! full section at once1 ! digg+ is usually />t$ by driv+ a small head+ or drift to locate & e/abli% ! axis ( ! tunnel1 & to facilitate dra9age 9 wet gr\nd4 ,^! advance gall]ies may be driv5 ei!r 9 ! upp] or 9 ! l[] "p ( ! section1 z ! local conditions & *oice ( ! eng9e] dictate4 ,:e!r ! advance gall]y is locat$ at ! top or at ! bottom ( ! section makes no diff]5ce 9 ! mode ( enl>g+ ! pr(ile4 ,?is "w always beg9s at ! upp] "p ( ! section4 ,a c5t] top head+ is driv5 & /rutt$ by erect+ po/s c>ry+ longitud9al b>s support+ transv]se pol+-bo>ds4 ,?is head+ is imm$iately wid5$ by digg+ away ! e>? at ea* side1 & by /rutt+ ! op5+ by tempor>y po/s re/+ on block+1 & c>ry+ longitud9al b>s support+ pol+-bo>ds4 ,?is process ( wid5+ is cont9u$ 9 ?is mann] until ! full ro( section1 ,no4 #a1 ,fig4 #hd1 is op5$1 :5 a heavy transv]se sill is laid1 & p]man5t /ruts are erect$ f x to ! longitud9al b>s1 ! tempor>y po/s & block+ be+ remov$4 ,! excavation ( "p ,no4 #b !n beg9s by op5+ a c5t] tr5* & wid5+ x on ea* side1 tempor>y po/s be+ erect$ to support ! sill above4 ,z soon z "p ,no4 #b is fully excavat$1 a second transv]se sill is plac$ bel[ ! fir/1 & /ruts are plac$ betwe5 !m4 ,! excavation ( "p ,no4 #c is c>ri$ out 9 exactly ! same mann] z 0 "p ,no4 #b4 ,! l5g?s ( ! v>i\s sections1 ,nos4 #a1 #b1 & #c1 g5]ally run f #ab ft4 to #bj ft41 dep5d+ ^u ! "* ( ! soil4 ,/rutt+4--,! /rutt+ 9 ! ,engli% me?od ( tunnel+ consi/s ( a transv]se framework set close to ! face ( ! excavation1 :i* supports "o end ( ! longitud9al cr[n b>s1 ! o!r ends ( :i* re/ on ! complet$ l9+4 ,! transv]se framework is compos$ ( ?ree horizontal sills arrang$ & support$ z %[n by ,fig4 #he4 ,! bottom sill ,a is c>ri$ by v]tical po/s re/+ on block+ on ! floor ( ! excavation4 ,f ! bottom sill v]tical /ruts rise to support ! middle sill ,b4 ,! top sill1 or m9]s' sill ,c1 is c>ri$ by v]tical po/s or /ruts ris+ f ! middle sill ,b4 ,! v]tical /ruts are usually r\nd timb]s f #f ins4 to #h ins4 9 diamet]2 & ! sills are squ>e timb]s ( suffici5t section to c>ry ! v]tical loads1 & g5]ally made up ( two po/s sc>f-jo9t$ & butt$ to p]mit !m to be m easily h&l$4 ,9 firm soils ! /ruts betwe5 ! sills are all set v]tically1 b ^? at ! extreme sides ( ! ro( section are incl9$4 ,9 loose soils1 h[ev]1 :]e ! sides ( ! excavation mu/ be %or$1 ! ,v-brac+ %[n by ,fig4 #he is employ$ betwe5 "o or m pairs ( sills z ! conditions necessitate4 ,! mann] ( hold+ ! transv]se framework upright is expla9$ q cle>ly by ,fig4 #he2 incl9$ props ext5d+ f ! complet$ masonry to ! sills ( ! framework be+ employ$4 ,two props are us$ to ea* sill4 ,sometimes1 9 addition to ! props %[n1 ano!r ne>ly horizontal prop ext5ds f ! cr[n ( ! ar* masonry to ! middle piece ( ! /rutt+4 ,illu/ration3 ,,fig4 #he4--,sket*es ,%[+ ,con/ruction ( ,/rutt+1 ,engli% ,me?od4 ,ref]r+ to ,fig4 #he1 x w be obs]v$ t ! longitud9al cr[n b>s are above ! extrados ( ! ro( ar*4 ,:51 !re=e1 ! l9+ masonry has be5 complet$ close up to ! transv]se framework1 ! latt] is remov$1 leav+ ! cr[n b>s re/+ on ! ar* masonry2 & excavation1 :i* has be5 /opp$ :ile ! masonry 0 be+ laid1 is cont9u$ = ano!r #ab ft4 to #bj ft41 & ! transv]se framework is erect$ at ! face1 & brac$ or propp$ aga9/ ! complet$ l9+ z %[n by ,fig4 #he4 ,! next /ep is to place ! cr[n b>s1 & ?is is done by pull+ !m ahead f _! orig9al position ov] ! masonry ( ! complet$ section ( ! ro( ar*4 ,x w be und]/ood t ! cr[n b>s are n pull$ ahead _! full l5g? at "o op]ation1 b are advanc$ by successive %ort movem5ts z ! excavation progresses1 _! out] ends be+ support$ by tempor>y po/s until ! transv]se framework is built at ! face ( ! excavation4 ,c5t]s4--,two /&>d =ms ( c5t]s are employ$ 9 ! ,engli% me?od ( tunnel+1 z %[n by ,figs4 #hf & #hg4 ,bo? consi/ ( an out] portion1 con/ruct$ mu* l a typical plank c5t]1 :i* is /r5g!n$ aga9/ di/ortion by an int]ior truss framework4 ,! elem5tal memb]s ( ?is truss framework take ! =m ( a que5-po/ truss1 z is %[n m p>ticul>ly by ,fig4 #hf4 ,9 ,fig4 #hg ! que5-po/ truss con/ruction is less easily di/+ui%$1 ow+ to ! cutt+ ( ! bottom tie-beam & o!r modifications1 b x c /ill be obs]v$4 ,! possibility ( cutt+ ! tie-beam z %[n 9 ,fig4 #hg1 )\t dang]1 is due to ! fact t ! lat]al pressures on ! haun*es ( ! c5t] c\nt]act ! t5d5cy ( ! c5t] to flatt5 "u load1 :i* is usually c\nt]act$ by ! tie-beam alone4 ,! object ( cutt+ ! tie-beam is to af=d room = ! props runn+ f ! complet$ masonry to ! transv]se framework ( ! /rutt+ z %[n by ,fig4 #he4 ,illu/ration3 ,,figs4 #hf & #hg4--,sket*es ( ,typical ,timb] ,ro(-,ar* ,c5t]s1 ,engli% ,me?od4 ,g5]ally f\r or five c5t]s are us$ = ea* l5g? ( ar* built4 ,!y are set up s t ! tie-beams re/ on d\ble opposite w$ges c>ri$ by a transv]se beam bel[4 ,?is transv]se beam 9 turn re/s on ano!r transv]se beam :i* is support$ by po/s c>ri$ on block+ on ! inv]t masonry4 ,x is usually made ) a butt$ jo9t at ! middle to p]mit its removal1 s9ce x is s long t ! masonry has to be built ar\nd its extreme ends4 ,! lagg+ is ( ! usual =m1 & re/s on ! ext]ior edges ( ! curv$ upp] memb] ( ! c5t]s4 ,masonry4--,9 ! ,engli% me?od ( tunnel+1 ! masonry beg9s ) ! con/ruction ( ! inv]t1 & proce$s to ! cr[n ( ! ar*4 ,! l9+ is built 9 l5g?s1 or successive r+s1 correspond+ to ! l5g? ( excavation1 :i*1 z previ\sly /at$1 is f #ab ft4 to #bj ft4 ,ea* r+ or l5g? ( l9+ t]m9ates close to ! transv]se /rutt+ frame erect$ at ! face ( ! excavation4 ,"w is fir/ begun on ! inv]t at ! po9t :]e ! prec$+ r+ ( masonry ends1 & is cont9u$ to ! transv]se /rutt+ frame at ! front ( ! excavation4 ,z fa/ z ! inv]t is complet$1 "w is begun on ! side walls4 ,9 v loose soils ! longitud9al b>s support+ ! sides ( ! excavation are remov$ aft] ! side walls are built2 b 9 firm] soils !y may be tak5 out "o by "o j ahead ( ! masonry1 or 9 v firm soils x may be possible to remove !m entirely be=e beg9n+ ! side walls4 ,9 all cases x is necess>y to fill ! space betwe5 ! masonry & ! walls ( ! excavation ) riprap or e>?4 ,to build ! ro( ar* ! c5t]s are fir/ erect$ z describ$ above1 & ! cr[n b>s are remov$ z previ\sly describ$ by pull+ !m ahead aft] ! ar* r+ is complet$4 ,z ) ! side walls1 ! vacant space betwe5 ! ar* r+ & ! ro( ( ! excavation mu/ be fill$ 94 ,usually e>? or small /ones are us$ = fill+2 b 9 v loose soils x is sometimes ! practice n to remove ! pol+-bo>ds1 b to support !m by %ort brick pill>s re/+ on ! ar* r+ & !n to fill ar\nd ^! pill>s4 ,haul+4--,to haul away ! mat]ial & take 9 supplies1 tracks are laid on ! inv]t masonry4 ,g5]ally ! p]man5t tracks are laid z fa/ z ! l9+ is complet$4 ,a %ort section ( tempor>y track is us$ to ext5d ?is p]man5t track close to ! "w ( ! advanc$ drift4 ,advantages & ,disadvantages4--,! great advantage ( ! ,engli% me?od ( tunnel+ is t ! masonry l9+ is built 9 "o piece f ! f\ndations to ! cr[n1 mak+ possible a /rong1 homog5e\s con/ruction4 ,x also possesses a decid$ advantage because ( ! simple me?ods ( haul+ :i* are possible3 !re be+ no diff]5ces ( level to surm\nt1 no hoi/+ ( c>s nor trans-%ipm5ts ( loads are necess>y4 ,! *ief disadvantage ( ! me?od is t ! excavators & masons "w alt]nately1 ?us mak+ ! progress ( ! "w sl[] p]haps ?an 9 any o!r me?od ( tunnel+ commonly employ$ "u simil> conditions4 ,?is disadvantage is ov]come to a consid]able ext5t :5 ! tunnel is excavat$ by %afts1 & ! "w at ! diff]5t head+s is s arrang$ t ! masons or excavators :5 fre$ f duty at "o head+ may be transf]r$ to ano!r :]e excavation or l9+ is to be done z ! case may be4 ,ano!r disadvantage ( ! ,engli% me?od arises f ! excavation ( ! full section at once1 :i* 9 un/able soils necessitates /rong & c>eful /rutt+1 & increases ! dang] ( cav+4 ,! fact also t ! ar* r+ has to c>ry ! weight ( ! cr[n b>s1 & _! load+ at "o end :ile ! masonry is gre51 increases ! *ances ( ! ar* be+ di/ort$4 ,conclusion4--,! ,engli% me?od ( tunnel+ 9 its entirety is conf9$ 9 actual practice pretty closely to ! c\ntry f :i* x receives its "n4 ,a possible ext5sion ( its use m g5]ally is consid]$ by _m z likely to foll[ ! developm5t ( a successful excavat+ ma*9e = s(t mat]ial4 ,! space af=d$ by ! op5+ ( ! full section at once1 especially adapts ! me?od to ! use ( excavators l1 = example1 ! endless *a9 bucket excavator us$ on ! ,c5tral ,london ,ry41 & illu/rat$ 9 ,fig4 #aa4 ,! me?od also furni%es an excell5t opportunity = electric haul+ & light+ dur+ con/ruction4 ,! ,engli% me?od ( tunnel+ has be5 us$ 9 build+ ! ,hoosac1 ,musconetcong1 ,allegh5y1 ,baltimore & ,potomac1 & o!r tunnels 9 ,am]ica4 ,! names ( ! ,european tunnels built by ?is me?od are too num]\s to m5tion "h4 ,,am]ican ,,me?od4 ,9 ?is c\ntry tunnels ?r\gh loose soils are excavat$ accord+ to ! 8,cr[n ,b>0 or ,am]ican ,me?od4 ,?is consi/s 9 op5+ ! :ole section ( ! tunnel be=e ! con/ruction ( ! l9+ z 9 ! ,engli% ,me?od4 ,x diff]s f ! ,engli% me?od1 h[ev]1 9 t _m timb] /ructures are erect$ = ! support ( ! ro(1 & t ! excavation & con/ruction ( ! l9+ are f> ap>t1 s all[+ ! m9]s & ! masons to "w cont9u\sly & )\t int]f]+ ) ea* o!r4 ,illu/ration3 ,,fig4 #hh4--,sequ5ce ( ,excavation 9 ! ,am]ican ,me?od4 ,illu/ration3 ,section ,a-,b4 ,,fig4 #hi4--,/rutt+ ! ,head+ 9 ! ,am]ican ,me?od4 ,illu/ration3 ,section ,c-,d4 ,,fig4 #ij4--,tempor>y ,timb]+ ( ! ,ro( 9 ! ,am]ican ,me?od4 ,illu/ration3 ,section ,e-,f4 ,,fig4 #ia4--,%[+ ,cr[n ,b>s ,support$ by ,segm5tal ,ar*es4 ,excavation4--,! diagram 9 ,fig4 #hh %[s ! sequ5ce ( excavation4 ,! "w beg9s by driv+ a c5tral head+ usually #g #h ft41 /rutt$ by means ( v]tical or batt] po/s & cap-piece4 ,fig4 #hi1aa ! props re/+ on foot blocks4 ,betwe5 ! cap-pieces ( ! consecutive frames are plac$ planks driv5 upw>d at a slightly incl9$ angle4 ,aft] ! head+ has be5 excavat$ & /rutt$1 ! floor is l[]$ by remov+ ! "p m>k$ #b 9 ! figure4 ,! two batt] po/s support+ ! cap-piece are n[ sub/itut$ by two long] ones re/+ on ! floor ( "p #b & abutt+ aga9/ longitud9al beams :i* are ins]t$ und]nea? ! cap-pieces4 ,^! longitud9al beams are call$ cr[n b>s4 ,! new batt] po/s are re/+ ei!r on foot blocks or sills accord+ to ! quality ( soil & !y are /rongly w$g$ to ! cr[n b>s4 ,on ea* side ( ^! cr[n b>s are ins]t$ pol+-bo>ds or planks close to ea* o!r1 :i* are driv5 d[nw>d4 ,! "p m>k$ #c 9 ! figure is remov$ by enl>g+ ! cut #a #b on bo? sides4 ,! plank1 ins]t$ above ! cr[n b>1 is driv5 9 ei!r prec$+ or foll[+ ! excavation & ano!r cr[n b> is ins]t$ at ! end ( ?is plank4 ,?is second cr[n b> is support$ by a prop ^: o!r end abuts aga9/ ! foot ( ! raft] /rutt+ ! head+4 ,betwe5 ?is cr[n b> & ! ro( ( ! excavation1 o!r planks are plac$ transv]sally to ! axis ( ! tunnel & are driv5 9 until !y are support$ by a new cr[n b>1 etc4 ,! v>i\s props support+ ! cr[n b>s are plac$ radially or 9 a fan-l mann]1 simil> to ! *>act]i/ic arrangem5t ( ! timb]+ 9 ! ,belgian me?od4 ,brac]s to /r5g!n ! timb]+ & ! ro( ( ! excavation are ins]t$ longitud9ally betwe5 ! v>i\s po/s & transv]sally betwe5 ! cr[n b>s1 ,fig4 #ij4 ,z a rule1 only ?ree or f\r ( ^! radial /ructures are tempor>ily erect$4 ,a tr5* is excavat$ at ! side ( ! "p m>k$ #c 9 ! figure to receive ! wall plate :i* is a heavy timb] laid on ! floor p>allel to ! longitud9al axis ( ! tunnel4 ,on ! wall plates are erect$ ! ar*$ timb] sets compos$ ( five or sev5 segm5ts ( hewn timb]s s z to =m a polygonal frame :i* is w$g$ to ! cr[n b>s & :i* w support ! ar* ( ! ro(4 ,aft] "o ( ^! segm5tal timb] sets is erect$ ! tempor>y radial /ructure is remov$ & ! upp] section ( ! tunnel is cle>$ ( any ob/ruction z ! pressures are transf]r$ to ! wall plates1 ,fig4 #ia4 ,! b5* m>k$ #d 9 ! figure is tak5 away & ! v]tical props ins]t$ "u ! wall plates1 ,fig4 #ib4 #aa ,figs4 #hi to #ia are tak5 f a pap] by ,s4 ,w4 ,hopk9s 9 ,h>v>d ,eng9e]+ ,j\rnal1 ,april1 '#jc1 on ! ,=t ,george tunnel4 ,illu/ration3 ,section ,g-,h4 ,longitud9al ,section4 ,,fig4 #ib4--,transv]sal & ,longitud9al ,section ( a ,tunnel ,excavat$ & ,/rutt$ ,accord+ to ! ,am]ican ,me?od4 ,/rutt+4--,! longitud9al /rutt+ is us$ 9 connection ) ! ,am]ican me?od ( tunnel+4 ,9 fact1 ! /rutt+ consi/s ( a s]ies ( longitud9al b>s support+ planks laid transv]sally to ! axis ( ! tunnel & abutt+ aga9/ ! ro( ( ! excavation4 ,^! cr[n b>s dur+ ! excavations & imm$iately aft] are tempor>ily support$ by radial timb]s =m+ almo/ a fan-l /ructure1 b ?is is soon sub/itut$ by a p]man5t "o compos$ ( a polygonal timb] frame ( five or sev5 segm5ts :i* are cut to dim5sions4 ,! batt] po/s ( ! head+1 ! radial po/s ( ! tempor>y timb] /ructure & ! cr[n b>s are all r\nd timb]s f #aj to #ab ins4 9 diamet]4 ,all ! o!r timb]s are squ>e edg$1 ! usual dim5sions be+ #aj #aj ins4 or #ab #ab ins4 ) ! exception ( ! wall plates :i* are #ad #ad ins4 ,! dim5sions ( ! v>i\s memb]s ( ! /rutt+ & ! di/ance ap>t ( ! diff]5t frames v>y ) ! quality ( ! soil4 ,= in/ance1 9 ord9>y loose soils ! frames are plac$ betwe5 #d to #f ft41 b 9 v s(t soils !y are erect$ only #c or #c ft4 ap>t4 ,*iefly 9 ! s\?we/1 9 tunnels excavat$ accord+ to ! ,am]ican me?od1 ! timb]+ has be5 left z regul> l9+ & x 0 only aft] _m ye>s :5 ?is tempor>y /ructure _h decay$ or 0 burn$ d[n1 t ! tunnels 7 l9$ ) masonry4 ,b 9 _m in/ances ! :ole timb] /ructure 0 left 9 place ev5 :5 ! tunnel 0 l9$ ) masonry imm$iately aft] ! excavation _h be5 made4 ,?is 0 usually done :5 ! tunnel 0 l9$ ) concrete masonry4 ,9 su* a case ! timb]+ 0 left to support ! pressures ( ! ro( :ile ! concrete 0 pla/ic & be=e x h>d5$4 ,c5t]s4--,9 ! ,am]ican me?od ! :ole section ( ! tunnel is op5 be=e ! con/ruction ( ! l9+1 ?us ! masonry c be built f ! f\ndations up4 ,! c5t]s are design$ s z to support only ! weight ( ! masonry dur+ its con/ruction & n ! pressures ( ! tunnel z 9 ! o!r me?ods & consequ5tly !y are ( light con/ruction4 ,! c5t]s describ$ 9 ! ,murray ,hill tunnel1 page #abc1 may be advantage\sly us$ 9 build+ ! concrete l9+ 9 tunnels ?r\gh loose soils excavat$ by ! ,am]ican me?od4 ,haul+4--,! excavation ( ! head+ & ! upp] section ( ! tunnel is usually f> ahead ( ! b5*1 consequ5tly ! haul+ ( bo? ! dbris & ! build+ mat]ials is made at two diff]5t levels1 viz41 on ! b5* & on ! floor ( ! tunnel4 ,:5 ! face ( ! head+ & ! excavation ( ! b5* are n m ?an #ej ft4 ap>t1 ! haul+ c be conv5i5tly done on ! tunnel floor1 :ile ! mat]ials & dbris on ! upp] section ( ! tunnel are haul$ by :eelb>r[s or light c>s propell$ by h&p[]4 ,= a great] di/ance1 h[ev]1 x is m conv5i5t to use light c>s runn+ on n>r[-gauge tracks all ?r\gh ! tunnel4 ,9 ?is case ! tracks on ! tunnel floor & on top ( ! b5* are connect$ by means ( an incl9$ plat=m :]e ! c>s may asc5d & desc5d )\t int]f]+ ) ! excavation ( ! b5*4 ,"h1 z a rule1 tunnels h be5 excavat$ 9 soils consid]$ good1 g5]ally ?r\gh rock1 :ile loose soils h be5 enc\nt]$ only 9 small sections4 ,! same me?od ( excavation = :atev] mat]ial is enc\nt]$ is c]ta9ly v conv5i5t1 z x af=ds a great regul>ity 9 ! "w2 h5ce its ext5sive use4 ,a great disadvantage ( ?is me?od is ! d\ble /rutt+1 viz41 ! polygonal & ! longitud9al /rutt+ succe$+ ea* o!r1 :]eas "o ( !m c\ld be easily sp>$4 ,ano!r defect is t x requires a l>g] am\nt ( excavation1 9 case ! /rutt+ is left 9 place4 ,,au/rian ,,me?od4 ,! ,au/rian full-section me?od ( tunnel+ ?r\gh s(t gr\nd 0 fir/ us$ 9 con/ruct+ ! ,ob]au tunnel on ! ,leipsic & ,dresd5 ,r4,r41 9 ,au/ria 9 #ahcg4 ,x consi/s 9 excavat+ ! full section & build+ up ! l9+ masonry f ! f\ndations z 9 ! ,engli%1 b ) ! important exception t ! inv]t is built la/ in/ead ( fir/ 9 all cases except :]e ! pres5ce ( v loose soil requires its con/ruction fir/4 ,a /ill m important diff]5ce 9 ! two me?ods is t ! excavation is c>ri$ out 9 small] sections & is cont9u\s 9 ! ,au/rian me?od in/ead ( alt]nat+ ) ! mason "w z x does 9 ! ,engli% me?od4 ,excavation4--,! excavation 9 ! ,au/rian me?od beg9s by driv+ ! bottom c5t] drift ,no4 #a1 ,fig4 #ic1 ris+ f ! floor ( ! tunnel section ne>ly to ! height ( ! spr++ l9es ( ! ro( ar*4 ,:5 ?is drift has be5 driv5 ahead a di/ance v>y+ f #ab ft4 to #bj ft4 or sometimes m1 ! excavation ( ! c5t] top head+ ,no4 #b is driv5 = ! same di/ance4 ,! next op]ation is to remove "p ,no4 #c1 ?us =m+ a c5tral passage ! full dep? ( ! tunnel section at ! c5t]4 ,?is tr5* is enl>g$ by remov+ p>ts ,nos4 #d1 #e1 #f1 #g1 & #h 9 ! ord] nam$ until ! full section is op5$4 ,a modification ( ?is plan ( excavation is %[n by ,fig4 #id :i* is us$ 9 firm soils4 ,illu/ration3 ,,figs4 #ic & #id4--;,diagrams ,%[+ ,sequ5ce ( ,excavation 9 ,au/rian ,me?od ( ,tunnel+4 ,/rutt+4--,ea* "p ( ! section is /rutt$ z fa/ z x is excavat$4 ,! c5t] bottom drift fir/ excavat$ is /rutt$ by lay+ a transv]se sill across ! floor1 rais+ two side po/s f x1 & capp+ !m ) a transv]se timb] hav+ its ends project+ beyond ! side po/s & halv$ z %[n by ,fig4 #ie4 ,! top c5t] head+ ,no4 #b1 :i* is next excavat$1 is /rutt$ by means ( two side po/s re/+ on block+ & c>ry+ a transv]se cap z also %[n by ,fig4 #ie4 ,sometimes ! side po/s 9 ! head+ /rutt+-frames are also c>ri$ on a transv]se sill z are ^? ( ! bottom drift4 ,?is con/ruction is usually adopt$ 9 loose soils4 ,:5 ! sill is employ$1 ! middle "p1 ,no4 #c1 is /rutt$ by ins]t+ side po/s betwe5 ! bottom ( ! top sill & ! cap ( ! frame 9 ! drift bel[4 ,:51 h[ev]1 ! po/s ( ! top head+ frame are c>ri$ on block+1 x is ! practice to replace !m ) long po/s ris+ f ! cap ( ! bottom drift frame to ! cap ( ! top head+ frame4 ,fur!r1 :5 ! int]m$iate sill is employ$ at ! bottom level ( ! top head+ x projects beyond ! side po/s & has its ends halv$4 ,illu/ration3 ,,figs4 #ie to #ig4--,sket*es ,%[+ ,con/ruction ( ,/rutt+1 ,au/rian ,me?od4 ,aft] ! completion ( ! c5t] tr5* /rutt+ ! next task is to /rut p>ts ,nos4 #d & #e4 ,?is is done by cont9u+ ! upp] sill by means ( a timb] hav+ "o end halv$ to jo9 ) ! project+ end ( ! sill 9 position4 ,?is ext5sion timb] is %[n at a1 ,fig4 #if4 ,! next op]ation is to place ! timb] b1 hav+ "o end re/+ on ! cap-piece ( ! top head+ frame & ! o!r bevel$ & re/+ on ! top ( ! sill a ne> ! end4 ,! timb] b is laid tang5t to ! curve ( ! ro( ar*1 & to support x aga9/ flexure ! /rut c is ins]t$ z %[n4 ,to support ! ?ru/ ( ?is /rut ! additional po/ d is ins]t$ & ! orig9al bottom head+ frame is re9=c$ z %[n4 ,! next /ep is to ins]t ! /rut e1 & :5 ?is & ! previ\s con/ruction are duplicat$ on ! opposite side ( ! tunnel section we h ! /rutt+ ( ! p>ts ,nos4 #a to #e2 inclusive1 complete4 ,"p ,no4 #f is !n remov$ & /rutt$ by ext5d+ ! bottom drift cap-piece by a timb] simil> to timb] a above1 & !n by ins]t+ a side /rut betwe5 ! out] ends ( ^! two timb]s1 z indicat$ by ,fig4 #ig4 ,z ! f9al p>ts4 ,nos4 #g & #h1 are remov$1 ! incl9$ prop a1 ,fig4 #ig1 is ins]t$ z %[n4 ,:5 ! soil is loose "s ( ! memb]s ( ! framework are d\bl$ & additional brac+ is introduc$ z %[n by ,fig4 #ig4 ,! frames j describ$ are plac$ at int]vals ( ab\t #d ft4 along ! excavation1 & are brac$ ap>t by horizontal /ruts4 ,"s ( ! longitud9al be>+ beams1 z at b1 ,fig4 #ig1 also ext5d ?r\gh two or ?ree frames1 & help to tie !m toge!r4 ,f9ally1 ! longitud9al pol+-bo>ds ext5d+ f "o frame to ! next along ! walls ( ! excavation s]ve to connect !m toge!r4 ,! %ort transv]se beam c1 ,fig4 #ij1 locat$ j above ! floor ( ! inv]t1 s]ves to c>ry ! plank+ ^u :i* ! tra9 c> tracks are laid4 ,besides ! timb] /rutt+ peculi> to ! ,au/rian me?od1 ! ,rziha iron /rutt+ describ$ 9 a previ\s *apt] is frequ5tly us$ 9 tunnel+ by ! ,au/rian process4 ,illu/ration3 ,,fig4 #ih4--,sket* ,%[+ ,mann] ( ,con/ruct+ ! ,l9+ ,masonry1 ,au/rian ,me?od4 ,c5t]s4--,! two =ms ( c5t]s us$ 9 ! ,engli% me?od ( tunnel+ are also us$ 9 ! ,au/rian me?od4 ,"o ( ! me?ods ( support+ ^! c5t]s is %[n by ,fig4 #ih4 ,! tie-beam ( ! c5t] re/s on longitud9al timb]s c>ri$ by ! /rutt+ frames & int]m$iate props4 ,9 s+le-track tunnels x is ! frequ5t practice also to c>ry ! ends ( ! tie-beams 9 recesses left 9 ! side wall masonry1 ) int]m$iate props ins]t$ to prev5t flexure at ! c5t]4 ,:5 ! ,rziha iron /rutt+ is employ$1 x also s]ves = ! c5t]+ ^u :i* ! ar* masonry is built4 ,masonry4--,9 ! ,au/rian sy/em ( tunnel+1 ! l9+ is built f ! f\ndations ( ! side walls upw>d to ! cr[n ( ! ro( ar* 9 l5g?s 9 consecutive r+s equal to ! l5g?s ( ! consecutive op5+s ( ! full section1 or f #ab ft4 to #bj ft4 long4 ,except 9 infrequ5t cases 9 v loose mat]ials ! inv]t is ! la/ "p ( ! masonry to be built1 s9ce to build x fir/ requires ! removal ( ! /rutt+ :i* _c easily or safely be accompli%$ until ! side walls & ro( ar* are complet$4 ,z ! side wall f\ndations are built1 h[ev]1 _! int]ior faces are left incl9$1 z %[n by ,figs4 #ig & #ih1 ready = ! ins]tion ( ! inv]t1 & are mean:ile kept f slid+ inw>d by ! ins]tion ( block+ betwe5 !m & ! bottom ( ! /rutt+4 ,fig4 #ih %[s ! nature ( ?is block+1 & also ! mann] 9 :i* ! side wall & ro( ar* masonry is c>ri$ upw>d4 ,f9ally :5 ! ro( ar* is key$ & ! c5t]s are /ruck1 ! /rutt+ is tak5 d[n & ! inv]t is built4 ,advantages & ,disadvantages4--,! pr9cipal advantages claim$ = ! ,au/rian me?od ( tunnel+ are3 7#a7 ,! excavation be+ conduct$ by driv+ a l>ge numb] ( consecutive small gall]ies1 :i* are imm$iately /rutt$1 !re is little di/urbance ( ! surr\nd+ mat]ial2 7#b7 ! polygonal type ( /rutt+ adopt$ is easily erect$ & ( great /r5g? aga9/ symmetrical pressures2 7#c7 ! masonry1 be+ built f ! f\ndations up1 is a s+le homog5e\s /ructure1 & is ?us bett] able to )/& dang]\s pressures2 7#d7 ! excavation is s conduct$ t ! masons & excavators d n int]f]e1 & bo? c "w at ! same "t4 ,! disadvantages :i* ! me?od possesses are3 7#a7 ,! /rutt+ :ile v /rong "u symmetrical pressures1 ei!r v]tical or lat]al1 is di/ort$ easily by unsymmetrical v]tical or lat]al pressures1 & by pressure 9 ! direction ( ! axis ( ! tunnel2 7#b7 ! con/ruction ( ! inv]t la/ exposes ! side walls to ! dang] ( be+ squeez$ toge!r1 caus+ a rotation ( ! ar* ( ! nature discuss$ 9 describ+ ! ,belgian me?od ( tunnel+4 ,,*apt] ,,xv4 ,,special ,,trea*]\s ,,gr\nd ,,me?od2 ,,italian ,,me?od2 ,,quicks& ,,tunnel+2 ,,pilot ,,me?od4 ,,italian ,,me?od4 ,! ,italian me?od ( tunnel+ 0 fir/ employ$ 9 con/ruct+ ! ,cri/9a tunnel on ! ,foggia ,b5ev5to ,r4,r4 9 ,italy4 ,?is tunnel p5etrat$ a lam9at$ clay ( ! mo/ trea*]\s "*1 & aft] v>i\s o!r s(t-gr\nd me?ods ( tunnel+ _h be5 tri$ & _h fail$1 ,mr4 ,procke1 ! eng9e]1 devis$ & us$ successfully ! me?od :i* is n[ kn[n z ! ,italian or ,cri/9a me?od4 ,! ,italian me?od is ess5tially a trea*]\s soil me?od4 ,x consi/s 9 excavat+ ! bottom half ( ! section by means ( sev]al successive drifts1 & build+ ! inv]t & side walls2 ! space is !n refill$ & ! upp] half ( ! section is excavat$1 & ! rema9d] ( ! side walls & ! ro( ar* are built2 f9ally1 ! e>? fill+ 9 ! l[] half ( ! section is re-excavat$ & ! tunnel complet$4 ,! me?od is an exp5sive "o1 b x has prov$ rem>kably successful 9 trea*]\s soils su* z ^? ( ! ,ap5n9e ,m\nta9s1 9 :i* "s ( ! mo/ notable ,italian tunnels are locat$4 ,x is1 moreov]1 a s+le-track tunnel me?od1 s9ce any soil :i* is s trea*]\s z to w>rant its use is too trea*]\s to p]mit an op5+ to be excavat$ ( suffici5t size = a d\ble-track railway1 except by ! use ( %ields4 ,excavation4--,! plan ( excavation 9 ! ,italian me?od is %[n by ! diagram ,fig4 #ii4 ,"w is begun by driv+ ! c5t] bottom head+ ,no4 #a1 & ?is is wid5$ by tak+ out p>ts ,no4 #b4 ,f9ally "p ,no4 #c is remov$1 & ! l[] half ( ! section is op54 ,z soon z ! inv]t & side wall masonry has be5 built 9 ?is excavation1 p>ts ,no4 #b are fill$ 9 aga9 ) e>?4 ,! excavation ( ! c5t] top head+ ,no4 #d is !n begun1 & is enl>g$ by remov+ ! e>? ( "p ,no4 #e4 ,! faces ( ?is la/ "p are incl9$ s z to r$uce _! t5d5cy to slide1 & to p]mit ( a great] numb] ( radial /ruts to be plac$4 ,next1 p>ts ,no4 #f are excavat$1 & :5 ?is is done ! entire section1 except = ! ?9 /rip ,no4 #g1 has be5 op5$4 ,at ! ends ( "p ,no4 #g n>r[ tr5*es are sunk to rea* ! tops ( ! side walls already con/ruct$ 9 ! l[] half ( ! section4 ,! masonry is !n complet$ = ! upp] half ( ! section1 & "p ,no4 #g & ! fill+ 9 p>ts ,no4 #b are remov$4 ,! v>i\s drifts & head+s & ! p>ts excavat$ to enl>ge !m are seldom excavat$ m ?an f #f ft4 to #aj ft4 ahead ( ! l9+4 ,illu/ration3 ,,fig4 #ii4--;,diagram ,%[+ ,sequ5ce ( ,excavation 9 ,italian ,me?od ( ,tunnel+4 ,illu/ration3 ,,fig4 #ajj4--,sket* ,%[+ ,/rutt+ = ,l[] ,"p ( ,section4 ,/rutt+4--,! bottom c5t] drift1 :i* is fir/ driv51 is /rutt$ by means ( frames consi/+ ( side po/s re/+ on floor blocks & c>ry+ a cap-piece4 ,pol+-bo>ds are plac$ ar\nd ! walls1 /ret*+ f "o frame to ! next4 ,z soon z ! inv]t is suffici5tly complet$ to p]mit x1 ! side po/s ( ! /rutt+ frames are replac$ by %ort /ruts re/+ on ! inv]t masonry z %[n by ,fig4 #ajj4 ,to p]mit ! old side po/s to be remov$ & ! new %ort] ones to be ins]t$1 ! cap-piece ( ! frame is tempor>ily support$ by incl9$ props arrang$ z %[n by ,fig4 #ajc4 ,:5 p>ts ,no4 #b are excavat$ ! ro( is /rutt$ by ins]t+ ! transv]se caps a1 ,fig4 #ajj1 ! out] ends ( :i* are c>ri$ by ! sy/em ( /ruts b1 c1 d1 & e4 ,! longitud9al pol+-bo>ds support+ ! ceil+ & walls are held 9 place by ! cap a & ! side timb] e4 ,to /iff5 ! frames longitud9ally ( ! tunnel1 horizontal longitud9al /ruts are ins]t$ betwe5 !m4 ,! excavation ( ! upp] half ( ! tunnel section is /rutt$ z 9 ! ,belgian me?od1 ) radial /ruts c>ry+ longitud9al ro( b>s & transv]se pol+-bo>ds4 ,on acc\nt ( ! enorm\s pressures develop$ by ! trea*]\s soils 9 :i* only is ! ,italian me?od employ$1 ! radial /rutt+ frames & cr[n b>s mu/ be ( great /r5g?1 :ile ! successive frames mu/ be plac$ at frequ5t int]vals1 usually n m ?an #c ft4 ,aft] ! masonry side walls h be5 built 9 ! l[] "p ( ! excavation1 longitud9al planks are laid aga9/ ! side po/s ( ! c5t] bottom drift frames1 to =m an enclosure = ! fill+-9 ( p>ts ,no4 #b4 ,! object ( ?is fill+ is pr9cipally to prev5t ! squeez+-9 ( ! side walls4 ,illu/ration3 ,,figs4 #aja & #aja;,a4--,sket*es ,%[+ ,con/ruction ( ,c5t]s1 ,italian ,me?od4 ,c5t]s4--,ow+ to ! great pressures to be resi/$ 9 ! trea*]\s soils 9 :i* ! ,italian me?od is us$1 ! con/ruction ( ! c5t]s has to be v /rong & rigid4 ,figs4 #aja & #aja;,a %[ two common types ( c5t] con/ruction us$ ) ?is me?od4 ,! con/ruction %[n 9 ,fig4 #aja is a /rong "o :]e only pressures normal to ! axis ( ! tunnel h to be )/ood1 b x is likely to twi/ "u pressures p>allel to ! axis ( ! tunnel4 ,9 ! con/ruction %[n by ,fig4 #aja;,a1 special provision is made to resi/ pressures normal to ! plane ( ! c5t] or twi/+ pressures1 by ! /r5g? ( ! transv]se brac+ ext5d+ horizontally across ! c5t]4 ,illu/ration3 ,,fig4 #ajb4--,sket* ,%[+ ,inv]t & ,f\ndation ,masonry1 ,italian ,me?od4 ,masonry4--,! con/ruction ( ! masonry l9+ beg9s ) ! inv]t1 z indicat$ by ,fig4 #ajj1 & is c>ri$ up to ! ro( ( p>ts ,no4 #b1 z already indicat$1 & is !n discont9u$ until ! upp] p>ts ,nos4 #d1 #e1 & #f are excavat$4 ,! next /ep is to s9k side tr5*es at ! ends ( "p ,no4 #g1 :i* rea* to ! top ( ! complet$ side walls4 ,?is op]ation leaves ! way cle> to f9i% ! side walls & to con/ruct ! ro( ar* 9 ! ord9>y mann] ( su* "w 9 tunnel+4 ,s9ce ?is me?od ( tunnel+ is us$ only 9 v s(t gr\nd :i* yields "u load1 ! usual practice is to con/ruct ! inv]t & side walls on a cont9u\s f\ndation c\rse ( concrete z indicat$ by ,fig4 #ajb4 ,! l9+ is usually built 9 successive r+s1 & ! usual precautions are tak5 ) respect to fill+ 9 ! voids beh9d ! l9+4 ,! ?ickness ( ! l9+ is bas$ ^u ! figures = lam9at$ clay ( ! ?ird v>iety giv5 9 ,table ,,ii4 ,haul+4--,! sy/em ( haul+ adopt$ ) ?is me?od ( tunnel+ is v simple1 s9ce ! excavation ( ! v>i\s p>ts is driv5 only f #f ft4 to #aj ft4 ahead1 & ! "w progresses sl[ly to all[ = ! con/ruction ( ! heavy /rutt+ requir$4 ,to take away ! mat]ial f ! c5t] bottom drift1 n>r[-gauge tracks c>ri$ by cross-beams betwe5 ! side po/s above ! floor l9e are employ$4 ,?is same n>r[-gauge l9e is employ$ to take away a portion ( p>ts ,no4 #b1 ! rema9+ portion be+ left & us$ = ! refill+ aft] ! bottom portion ( ! l9+ has be5 built1 z previ\sly describ$4 ,! upp] half ( ! section be+ excavat$1 z 9 ! ,belgian me?od1 ! sy/em ( haul+ ) incl9$ planes to ! tunnel floor bel[1 :i* is a *>act]i/ic ( t me?od1 may be employ$4 ,x is ! m usual practice1 h[ev]1 s9ce ! excavation is c>ri$ s little a di/ance ahead & progresses s sl[ly1 to h&le ! spoil f ! upp] "p ( ! section by :eelb>r[s :i* dump x into ! c>s runn+ on ! tunnel floor bel[4 ,h& labor is also us$ to raise ! con/ruction mat]ials us$ 9 build+ ! upp] section4 ,! tracks on ! tunnel floor1 besides ext5d+ to ! front ( ! advanc$ bottom c5t] drift1 h "r & left swit*es to be employ$ 9 remov+ ! refill+ 9 p>ts ,no4 #b1 ! spoil f ! upp] "p ( ! section1 & ! mat]ial ( "p ,no4 #g4 ,fig4 #ajc is a longitud9al section %[+ ! plan ( excavation & /rutt+ adopt$ ) ! ,italian me?od4 ,illu/ration3 ,,fig4 #ajc4--,sket* ,%[+ ,longitud9al ,section ( a ,tunnel "u ,con/ruction1 ,italian ,me?od4 ,modifications4--,x (t5 happ5s t ! fill+ plac$ betwe5 ! side walls & ! plank+1 :i* is practically ! space compris$ by p>ts ,no4 #b1 is n suffici5t to resi/ ! inw>d pressure ( ! walls1 & !y tip inw>d4 ,9 ^! cases a common exp$i5t is to sub/itute = ! e>? fill+ a tempor>y masonry ar* sprung betwe5 ! side walls ) its feet ne> ! bottom ( ! walls1 & its cr[n j bel[ ! level ( _! tops1 z %[n by ,fig4 #ajg4 ,?is con/ruction 0 employ$ 9 ! ,/azza tunnel 9 ,italy4 ,9 ?is tunnel ! excavation 0 begun by driv+ ! c5t] drift1 ,no4 #a1 ,fig4 #ajd1 & imm$iately /rutt+ x z %[n by ,fig4 #aje4 ,! o!r p>ts1 ,nos4 #b & #c1 complet+ ! l[] portion ( ! section1 7 !n tak5 out & /rutt$4 ,:ile "p ,no4 #b 0 be+ excavat$ at ! bottom1 & ! c5t] "p ( ! inv]t built1 ! longitud9al cr[n b>s c>ry+ ! ro( ( ! excavation 7 c>ri$ tempor>ily by ! incl9$ props %[n by ,fig4 #ajf4 ,aft] complet+ ! inv]t & ! side walls to a height ( #b or #c ft41 a ?ick masonry ar* 0 sprung betwe5 ! side walls1 z %[n 9 transv]se section by ,fig4 #ajg1 & 9 longitud9al section by ,fig4 #ajf4 ,?is ar* brac$ ! side walls aga9/ tipp+ inw>d1 & c>ri$ %ort /ruts to support ! cr[n b>s4 ,! haun*es ( ! ar* 7 also fill$ 9 ) ramm$ e>?4 ,! upp] half ( ! section 0 excavat$1 /rutt$1 & l9$ z 9 ! /&>d ,italian me?od previ\sly describ$4 ,:5 ! l9+ 0 complet$1 ! ar* ins]t$ betwe5 ! side walls 0 brok5 d[n & remov$4 ,illu/ration3 ,,fig4 #ajd4--,sket* ,%[+ ,sequ5ce ( ,excavation1 ,/azza ,tunnel4 ,illu/ration3 ,,fig4 #aje4--,sket* ,%[+ ,me?od ( ,/rutt+ ,fir/ ,drift1 ,/azza ,tunnel4 ,illu/ration3 ,,figs4 #ajf & #ajg4--,sket*es ,%[+ ,tempor>y ,/rutt+ ,ar* ,con/ruction1 ,/azza ,tunnel4 ,advantages & ,disadvantages4--,! great advantage claim$ = ! ,italian me?od ( tunnel+ is t x is built 9 two sep>ate p>ts1 ea* ( :i* is sep>ately excavat$1 /rutt$1 & l9$1 & ?us c be employ$ successfully 9 v trea*]\s soils4 ,its *ief disadvantage is its excessive co/1 :i* limits its use to tunnels ?r\gh trea*]\s soils :]e o!r me?ods ( timb]+ _c be us$4 ,,quicks& ,,tunnel+4 ,:5 an und]gr\nd /ream ( wat] passes ) =ce ?r\gh a b$ ( s& x produces ! ph5om5on kn[n z quicks&4 ,?is ph5om5on is due to ! f95ess ( ! p>ticles ( s& & to ! =ce ( ! wat]1 & its activity is directly proportional to !m4 ,:5 s& is conf9$ x furni%es a good f\ndation b$1 s9ce x is practically incompressible4 ,to "w successfully 9 quicks&1 !re=e1 x is necess>y to dra9 x & to conf9e ! p>ticles ( s& s t !y _c fl[ away ) ! wat]4 ,?is obs]vation sugge/s ! mode ( proc$ure adopt$ 9 excavat+ tunnels ?r\gh quicks&1 :i* is to dra9 ! tunnel section by op5+ a gall]y at its bottom to collect & c>ry away ! wat]1 & to prev5t ! movem5t or fl[+ ( ! s& by /rutt+ ! sides ( ! excavation ) a tight plank+4 ,! s& hav+ to be dra9$ & conf9$ z describ$1 ! ord9>y me?ods ( s(t-gr\nd tunnel+ mu/ be employ$1 ) ! foll[+ modifications3 7#a7 ,! fir/ "w to be p]=m$ is to op5 a bottom gall]y to dra9 ! tunnel4 ,?is gall]y %\ld be l9$ ) bo>ds laid close & brac$ suffici5tly by int]ior frames to prev5t di/ortion ( ! l9+4 ,! int]/ices or seams betwe5 ! l9+ bo>ds %\ld be pack$ ) /raw s z to p]mit ! p]colation ( wat] & yet prev5t ! movem5t ( ! s&4 7#b7 ,z fa/ z ! excavation progresses its walls %\ld be /rutt$ by planks laid close1 & held 9 position by int]ior framework2 ! seams betwe5 ! plank %\ld be pack$ ) /raw4 7#c7 ,! masonry l9+ %\ld be built 9 successive r+s1 & ! "w s arrang$ t ! wat] seep+ 9 at ! sides & ro( is collect$ & remov$ f ! tunnel imm$iately4 ,excavation4--,! be/ & mo/ commonly employ$ me?od ( driv+ tunnels ?r\gh quicks& is a modification ( ! ,belgian me?od4 ,at fir/ sight x may appe> a haz>d\s "w to support ! ro( ar*1 z is ! *>act]i/ic ( ?is me?od1 on ! unexcavat$ soil bel[1 :5 ?is soil is quicks&1 b if ! s& is well conf9$ & dra9$ ! risk is really n v great4 ,next to ! ,belgian me?od ! ,g]man me?od is p]haps ! be/ = tunnel+ quicks&4 ,9 ^! comp>isons ! %ield sy/em ( tunnel+ is = ! "t be+ left out ( consid]ation4 ,?is me?od w be describ$ 9 succe$+ *apt]s4 ,:5ev] any ( ! sy/ems ( tunnel+ previ\sly describ$ are employ$1 ! fir/ task is always to op5 a dra9age gall]y at ! bottom ( ! section4 ,assum+ ! ,belgian me?od is to be ! "o adopt$1 ! fir/ "w is to drive a c5t] bottom drift1 ! floor ( :i* is at ! level ( ! extrados ( ! inv]t4 ,?is drift is imm$iately /rutt$ by successive transv]se frames made up ( a sill1 side po/s1 & a cap :i* support a close plank /rutt+ or l9+1 ) its jo9ts pack$ ) /raw4 ,betwe5 ! side po/s ( ea* cross-frame1 at ab\t ! height ( ! intrados ( ! inv]t1 a cross-beam is plac$2 & on ^! cross-beams a plank floor+ is laid1 :i* divides ! drift horizontally into two sections1 z %[n by ,fig4 #ajh2 ! l[] section =m+ a cov]$ dra9 = ! seepage wat]1 & ! upp] provid+ a passageway = workm5 & c>s4 ,! bottom drift is driv5 z f> ahead z practicable1 9 ord] to dra9 ! s& = z great a di/ance 9 advance ( ! "w z possible4 ,aft] ! con/ruction ( ! bottom dra9age drift ! excavation prop] is begun1 z x ord9>ily is 9 ! ,belgian me?od by driv+ a top c5t] head+1 z %[n by ,fig4 #ajh4 ,?is head+ is deep5$ & wid5$ aft] ! mann] usual to ! ,belgian me?od1 until ! top ( ! section is op5 d[n to ! spr++ l9es ( ! ro( ar*4 ,to collect ! seepage wat] f ! c5t] top head+ x is provid$ ) a c5t] bottom dra9 con/ruct$ l ! dra9 9 ! bottom drift1 z %[n by ,fig4 #ajh4 ,:5 ! top head+ is deep5$ to ! level ( ! spr++ l9es ( ! ro( ar*1 its bottom dra9 is recon/ruct$ at ! new level1 & s]ves to dra9 ! full top section op5$ = ! con/ruction ( ! ro( ar*4 ,?is top dra9 is usually con/ruct$ to empty into ! dra9 9 ! bottom drift4 ,illu/ration3 ,,fig4 #ajh4--,sket* ,%[+ ,prelim9>y ,dra9age ,gall]ies1 ,quicks& ,me?od4 ,illu/ration3 ,,fig4 #aji4--,sket* ,%[+ ,con/ruction ( ,ro( ,/rutt+1 ,quicks& ,me?od4 ,/rutt+4--,! me?od ( /rutt+ ! bottom drift has already be5 describ$4 ,= ! rema9d] ( ! excavation ! regul> ,belgian me?od ( radial ro( /rutt+-frames is employ$1 z %[n by ,fig4 #aji4 ,contr>y to :at might be expect$1 ! numb] ( radial /ruts requir$ is n usually great] ?an w\ld be us$ 9 _m o!r soils besides quicks&4 ,s+le-track railway tunnels h be5 con/ruct$ ?r\gh quicks& 9 sev]al in/ances :]e ! numb] ( radial props requir$ on ea* side ( ! c5t] did n exce$ f\r or five4 ,x is necess>y1 h[ev]1 to place ! pol+-bo>ds v close toge!r1 & to pack ! jo9ts betwe5 !m to prev5t ! infl[ ( ! f9e s&4 ,9 /rutt+ ! l[] "p ( ! section x is also necess>y to support ! sides ) tight plank+4 ,?is is usually held 9 place by longitud9al b>s brac$ by %ort /ruts aga9/ ! incl9$ props employ$ to c>ry ! ro( ar* :5 ! mat]ial on :i* !y orig9ally re/$ is remov$4 ,?is side /rutt+ is %[n at ! "r h& ( ,fig4 #aaj4 ,illu/ration3 ,,fig4 #aaj4--,sket* ,%[+ ,con/ruction ( ,masonry ,l9+1 ,quicks& ,me?od4 ,masonry4--,z soon z ! upp] "p ( ! section has be5 op5$ ! ro( ar* is built ) its feet re/+ on planks laid on ! unexcavat$ mat]ial bel[4 ,?is ar* is built exactly z 9 ! regul> ,belgian me?od previ\sly describ$1 us+ ! same =ms ( c5t]s & ! same me?ods ?r\gh\t1 except t ! pol+-bo>ds ( ! /rutt+ are usually left rema9+ above ! ar* masonry4 ,to prev5t ! possibility ( wat] p]colat+ ?r\gh ! ar* masonry1 _m eng9e]s also advise ! pla/]+ ( ! extrados ( ! ar* ) a lay] ( cem5t mort>4 ,?is pla/]+ is design$ to lead ! wat] along ! haun*es ( ! ar* & d[n beh9d ! side walls4 ,9 con/ruct+ ! masonry bel[ ! ro( ar* ! inv]t is built fir/1 contr>y to ! regul> ,belgian me?od1 & ! side walls are c>ri$ up on ea* side f ! inv]t masonry4 ,seepage holes are left 9 ! inv]t masonry1 & also 9 ! side walls j above ! intrados ( ! inv]t4 ,at ! c5t] ( ! inv]t a culv]t or dra9 is con/ruct$1 z %[n by ,fig4 #aaj1 inside ! inv]t masonry4 ,?is culv]t is commonly made ) an elliptical section ) its major axis horizontal1 & hav+ op5+s at frequ5t int]vals at its top4 ,! ?ickness ( ! l9+ masonry requir$ 9 quicks& is %[n by ,table ,,ii4 ,remov+ ! ,seepage ,wat]4--,aft] ! tunnel is complet$ ! wat] :i* seeps 9 ?r\gh ! weep-holes left 9 ! masonry passes out ( ! tunnel1 foll[+ ! direction ( ! desc5d+ grades4 ,dur+ con/ruction1 h[ev]1 special means w h to be provid$ = remov+ ! wat] f ! excavation1 _! "* dep5d+ ^u ! me?od ( excavation & ^u ! grades ( ! tunnel bottom4 ,:5 ! excavation is c>ri$ on f ! entrances only1 unless ! tunnel has a desc5d+ grade f ! c5t] t[>d ea* end1 ! tunnel floor 9 "o head+ w be bel[ ! level ( ! entrance1 or1 9 o!r words1 ! desc5d+ grade w be t[>d ! po9t :]e "w is go+ on1 :ile at ! opposite entrance ! grade w be desc5d+ f ! "w4 ,9 ! latt] case ! removal ( ! seepage wat] is easily accompli%$ by means ( a dra9age *annel along ! bottom ( ! excavation4 ,9 ! =m] case ! wat] :i* dra9s t[>d ! front is collect$ 9 a sump1 & if !re is n too great a diff]5ce 9 level betwe5 ?is sump & ! entrance1 a siphon may be us$ to remove x4 ,:]e ! siphon _c be us$1 pumps are in/all$ to remove ! wat]4 ,:5 ! tunnel is excavat$ by %afts ! condition ( "o high & "o l[ front1 z comp>$ ) ! level at ! %aft1 is _h at ea* %aft4 ,g5]ally1 !re=e1 a sump is con/ruct$ at ! bottom ( ! %aft2 ! culv]t f ! high front dra9s directly to ! %aft sump1 :ile ! wat] f ! l[-front sump is ei!r siphon$ or pump$ to ! %aft sump4 ,f ! %aft sump ! wat] is =c$ up ! %aft to ! surface by pumps4 ,,! ,,pilot ,,me?od4 ,! pilot sy/em ( tunnel+ has be5 successfully employ$ 9 con/ruct+ s(t-gr\nd sew] tunnels 9 ,am]ica by ! firm ( ,&]son ,b>r1 :i* controls ! pat5ts4 ,! mo/ important "w on :i* ! sy/em has be5 employ$ is ! ma9 relief sew] tunnel built 9 ,brooklyn1 ,n4,y41 9 #ahib4 ,?is "w compris$ #hjj ft4 ( circul> tunnel #ae ft4 9 diamet]1 #ddjj ft4 #ad ft4 9 diamet]1 #cbjj ft4 #ab ft4 9 diamet]1 & #ajjj ft4 #aj ft4 9 diamet]1 or #idjj ft4 ( tunnel altoge!r4 ,! me?od ( con/ruction by ! pilot sy/em is z foll[s3 ,%afts l>ge en\gh = ! prop] conveyance ( mat]ials f & into ! tunnel are sunk at su* places on ! l9e ( "w z are mo/ conv5i5t = ! purpose4 ,f ^! %afts a small tunnel1 te*nically a pilot1 ab\t #f ft4 9 diamet]1 compos$ ( roll$ boil] iron plates rivet$ to light angle irons on f\r sides1 p]=at$ = bolts1 & b5t to ! requir$ radius ( ! pilot1 is built into ! c5tral "p ( ! excavation on ! axis ( ! tunnel4 ,?is pilot is g5]ally kept ab\t #cj ft4 9 advance ( ! complet$ excavation1 z %[n by ,fig4 #aaa4 ,! mat]ial ar\nd ! ext]ior ( ! pilot is !n excavat$1 us+ ! pilot z a support = braces :i* radiate f x & secure 9 position ! plates ( ! outside %ell :i* holds ! s&1 gravel1 or o!r mat]ial 9 place until ! conc5tric r+s ( brick masonry are built4 ,ribs ( ,t-iron b5t to ! radius ( ! int]ior ( ! brick "w1 & support$ by ! braces radiat+ f ! pilot1 are us$ z c5t]+ supports = ! masonry4 ,on ^! ribs n>r[ lagg+-bo>ds are laid z ! con/ruction ( ! ar* proce$s1 ! braces hold+ ! %ell plates & ! sup]9cumb5t mass be+ remov$ z ! masonry progresses4 ,! key bricks ( ! ar*es are plac$ 9 position on +5i\sly contriv$ key-bo>ds1 ab\t #ab ins4 9 wid?1 :i* are fitt$ into rabbet$ lagg+-bo>ds "o aft] ano!r z ! key bricks are laid 9 place4 ,aft] ! masonry has be5 9 place at lea/ tw5ty-f\r h\rs1 all[+ ! cem5t mort> "t to set1 ! braces1 ribs1 & lagg+ :i* support x are remov$4 ,9 ! meantime ! excavation1 brac+1 pilot1 & ext]ior %ell h be5 c>ri$ =w>d1 prep>+ ! way = m masonry4 ,! top plates ( ! %ell are fir/ plac$ 9 position1 ! mat]ial be+ excavat$ 9 advance & support$ by light pol+-bo>ds2 !n ! side-plates are butt$ to ! top & ! adjo9+ side-plates4 ,9 ! pilot ! plates are unit$ cont9u\sly ar\nd ! p]imet] ( ! circle1 :ile 9 ! ext]ior %ell ! plates are us$ = ab\t "o-?ird ( ! p]imet] on top1 unless trea*]\s mat]ial is enc\nt]$1 :5 ! plates are cont9u$ d[n to ! spr++ l9es ( ! ar*4 ,?is iron l9+ is left 9 place4 ,! bottom is excavat$ s z to con=m to ! ext]ior l9es ( ! masonry4 ,! excavation foll[s s closely to ! out] l9es ( ! normal section ( ! tunnel t v little loss occurs1 ev5 9 bad mat]ial2 & !re is no loss :]e suffici5t bond exi/s 9 ! mat]ial to hold x 9 place until ! pol+-bo>ds are 9 position4 ,illu/ration3 ,brac+4 ,ar* ,con/ruction4 ,longitud9al ,section4 ,,fig4 #aaa4--,sket* ,%[+ ,pilot ,me?od ( ,tunnel+4 ,9 ! ,brooklyn sew] tunnel "w1 previ\sly m5tion$1 ! pilot 0 built ( /eel plates 94 ?ick1 #ab ins4 wide1 & #cg ins4 long1 roll$ to a radius ( #c ft4 ,/eel angles #d #d ins4 7 rivet$ along all f\r sides ( ea* plate1 & ! plates 7 bolt$ toge!r by -94 ma*9e-bolts4 ,! plates weigh$ #acf lbs4 ea*1 & six ( !m 7 requir$ to make "o complete r+ #f ft4 9 diamet]4 ,9 bolt+ !m toge!r1 iron %ims 7 plac$ betwe5 ! horizontal jo9ts to =m a foot+ = ! wood5 braces = ! %ell1 :i* radiate f ! pilot4 ,! %ell plates ( ! #ae-;ft4 section ( ! tunnel 7 ( ,no4 #aj /eel #ab ins4 wide & #cg ins4 long1 ) /eel angles #b #b ins41 rivet$ ar\nd ! edges ! same z = ! pilot1 & put toge!r ) -94 bolts4 ,^! plates weigh$ #fa lbs4 ea*1 & eighte5 ( !m 7 requir$ to make "o complete r+ #ae ft4 9 diamet]4 ,! plates = ! #ab-;ft4 section 7 ,no4 #ab /eel #ab ins4 wide ) #b #b -94 angles4 ,sev5te5 plates 7 requir$ to make a complete r+4 ,,*apt] ,,xvi4 ,,op5-,,cut ,,tunnel+ ,,me?ods2 ,,tunnels ,,"u ,,city ,,/reets2 ,,bo/on ,,subway ,,& ,,new ,,york ,,rapid ,,transit4 ,,op5-,,cut ,,tunnel+4 ,:5 a tunnel or rapid-transit subway has to be con/ruct$ at a small dep? bel[ ! surface1 ! excavation is g5]ally p]=m$ m economically by mak+ an op5 cut ?an by subt]ranean tunnel+ prop]4 ,! necess>y condition ( small dep? :i* makes op5-cut tunnel+ desirable is mo/ g5]ally f\nd 9 con/ruct+ rapid-transit subways or tunnels "u city /reets4 ,?is fact introduces ! *ief difficulties enc\nt]$ 9 su* "w1 s9ce ! surface traffic makes x necess>y to ob/ruct ! /reets z little z possible1 & has l$ to ! developm5t ( ! sev]al special me?ods commonly employ$ 9 p]=m+ x4 ,subways are usually con/ruct$ "u & along important /reets :]e electric c>s are runn+4 ,! eng9e]s h tak5 advantage ( ! pres5ce ( ^! l9es to facilitate ! con/ruction ( subways4 ,9 ,new ,york1 = in/ance1 ! tracks ( ! electric l9es 7 support$ by ca/-iron yokes #d or #e ft4 ap>t & 7 surr\nd$ by concrete1 leav+ only a l>ge holl[ space 9 ! middle = ! wires & trolleys4 ,! rails f #dj to #fj ft4 long =m$ almo/ a solid concrete /ructure = _! entire l5g?4 ,! tracks & ! /reet surface 7 support$ by horizontal beams ins]t$ und]nea? ! tracks4 ,^! 7 ! caps ( b5ts con/ruct$ und]gr\nd ^: raft]s 7 f9ally re/+ on ! subgrade ( ! propos$ subway4 ,! v>i\s me?ods = con/ruct+ ! subways may be classifi$ z foll[s3 7#a7 ,! s+le wide tr5* me?od2 7#b7 ! s+le n>r[ longitud9al tr5* me?od2 7#c7 ! p>allel longitud9al tr5* me?od2 7#d7 ! slice me?od4 ,s+le ,longitud9al ,tr5*4--,! simple/ mann] by :i* to con/ruct op5-cut tunnels is to op5 a s+le cut or tr5* ! full wid? ( ! tunnel masonry4 ,?is tr5* is /rutt$ by means ( side %eet+s ( v]tical planks1 held 9 place by transv]se braces ext5d+ across ! tr5* & abutt+ aga9/ longitud9al timb]s laid aga9/ ! %eet+ plank4 ,! l9+ is built 9 ?is tr5*1 & is !n fill$ ar\nd & above ) well-ramm$ e>?1 aft] :i* ! surface ( ! gr\nd is re/or$4 ,an especial m]it ( ! s+le longitud9al tr5* me?od ( op5-cut tunnel+ is t x p]mits ! con/ruction ( ! l9+ 9 a s+le piece f ! bottom up1 ?us enabl+ bett] workman%ip & /rong] con/ruction ?an :5 ! sep>ate p>ts are built at diff]5t times4 ,! great objection to ! me?od :5 x is us$ = build+ subways "u city /reets is1 t x occupies s mu* room t ! /reet usually has to be clos$ to regul> traffic4 ,= ?is reason ! s+le longitud9al tr5* me?od is seldom employ$1 except 9 ^? portions ( city subways :i* pass "u public squ>es or p>ks :]e room is pl5ty4 ,?is me?od 0 foll[$ 9 ! con/ruction ( ! ,new ,york subway1 ,section #b1 along ,elm ,/41 a new /reet to be op5$ to traffic aft] ! subway _h be5 complet$1 & at o!r po9ts :]e local conditions all[$ x4 ,illu/ration3 ,,fig4 #aab4--;,diagram ,%[+ ,sequ5ce ( ,con/ruction 9 ,op5-,cut ,tunnels4 ,a modification ( ?is me?od 0 us$ 9 ,contract ,section #f1 on upp] ,broadway4 ,! /reet at ?is po9t is v wide1 s by op5+ a tr5* z wide z ! propos$ f\r-track l9e ( ! subway !re /ill rema9$ room en\gh = ord9>y traffic4 ,! electric c> tracks 7 support$ by means ( trusses #fj or #gj ft4 long1 :i* 7 laid 9 c\ples p>allel to ! tracks & :i* re/$ on firm soil4 ,! soil "u ! c> tracks 0 remov$1 beg9n+ ) transv]sal cuts to receive ! ne$les :i* 7 ti$ to ! l[] *ord ( ! trusses by means ( iron /irrups4 ,aft] ! excavation _h rea*$ ! subgrade1 po/s 7 erect$ to support ! ne$les ?us =m+ b5ts ^u :i* ! tracks re/$4 ,! trusses 7 remov$ & advanc$ to ano!r section ( ! tunnel1 &1 9 ! cle> space left1 ! subway 0 built f f\ndation up4 ,! ,s+le ,n>r[ ,longitud9al ,tr5*4--,?is me?od 0 us$ on ,contract ,section #e1 ( ! ,new ,york subway 9 ord] to comply ) ! peculi> conditions ( ! traffic along #dbnd ,/4 ,on ?is /reet1 on acc\nt ( ! ,new ,york ,c5tral ,/ation1 !re is a con/ant heavy traffic1 :ile p$e/rians use ! nor!rn sidewalks almo/ exclusively4 ,a s+le longitud9al tr5* 0 !n op5$ along ! s\? side1 & f ?is tr5* all ! "w ( excavation & con/ruction 0 c>ri$ on4 ,at fir/ ! /eel /ructure ( ! subway 0 erect$ 9 ! tr5* & !n a small head+ 0 driv5 & /rutt$ "u & across ! surface-c> tracks4 ,aft]w>d heavy ,i-beams 7 ins]t$1 :i* re/$ ) "o end on top ( ! /eel b5ts & ! o!r end block$ to ! floor ( ! excavation4 ,^! ,i-beams 7 locat$ #e ft4 ap>t & !y support$ ! surface ( ! /reet by means ( longitud9al planks4 ,! soil 0 remov$ f ! wide space und]nea? ! ,i-beams & ! subway 0 con/ruct$ f ! f\ndation up4 ,:5 ! /ructure _h be5 complet$1 ! pack+ 0 plac$ betwe5 ! ro( ( ! /ructure & ! surface ( ! /reet1 ! ,i-beams )drawn & ! voids fill$ 94 ,p>allel ,longitud9al ,tr5*es4--,! p>allel longitud9al tr5* me?od ( op5-cut tunnel+ consi/s 9 excavat+ two n>r[ p>allel tr5*es = ! side walls1 leav+ ! c5t] core to be remov$ aft] ! side walls h be5 built4 ,! diagram1 ,fig4 #aab1 %[s ! sequ5ce ( op]ations 9 ?is me?od4 ,! two tr5*es ,no4 #a are fir/ excavat$ a little wid] ?an ! side wall masonry1 & /rutt$ z %[n by ,fig4 #aac4 ,at ! bottoms ( ^! tr5*es a f\ndation c\rse ( concrete is laid1 z %[n by ,fig4 #aad1 if ! gr\nd is s(t2 or ! masonry is />t$ directly on ! natural mat]ial1 if x is rock4 ,f ! f\ndations ! walls are c>ri$ up to ! level ( ! spr++ l9es ( ! ro( ar*1 if an ar* is us$2 or to ! level ( its ceil+1 if a flat ro( is us$4 ,aft] ! completion ( ! side walls1 ! portion ( ! excavation %[n at ,no4 #b1 ,fig4 #aab1 is remov$ a suffici5t dep? to enable ! ro( ar* to be built4 ,:5 ! ar* is complet$1 x is fill$ above ) well-ramm$ e>?1 & ! surface is re/or$4 ,! excavation ( "p ,no4 #c inclos$ by ! side walls & ro( ar* is c>ri$ on f ! entrances & f %afts left at int]vals along ! l9e4 ,illu/ration3 ,,fig4 #aac4--,sket* ,%[+ ,me?od ( ,timb]+ ,op5-,cut ,tunnels1 ,d\ble ,p>allel ,tr5* ,me?od4 ,illu/ration3 ,,fig4 #aad4--,side-,wall ,f\ndation ,con/ruction ,op5-,cut ,tunnels4 ,a modification ( ! me?od j describ$ 0 employ$ 9 con/ruct+ ! ,p>is und]gr\nd railways4 ,x consi/s 9 excavat+ a s+le longitud9al tr5* along "o side ( ! /reet1 & build+ ! side wall 9 x z previ\sly describ$4 ,:5 ?is side wall is complet$ to ! ro(1 ! "r half ( "p ,no4 #b1 ,fig4 #aab1 is excavat$ to ! l9e ,,ab1 & ! "r-h& half ( ! ro( ar* is built4 ,! space above ! ar* is !n refill$ & ! surface ( ! /reet re/or$1 aft] :i* ! left-h& tr5* is dug & ! side wall & ro(-ar* masonry is built j z 9 ! opposite half4 ,g5]ally ! "w is prosecut$ by op5+ up l5g?s ( tr5* at consid]able int]vals along ! /reet & alt]nately on ! left-& "r-h& sides4 ,by ?is me?od "o-half ( ! /reet wid? is ev]y:]e op5 to traffic1 ! travel simply pass+ f "o side ( ! /reet to ! o!r to avoid ! excavation4 ,:5 ! l9+ has be5 complet$1 ! c5t] core ( e>? inclos$ by x is remov$ f ! entrances & %afts1 leav+ ! tunnel f9i%$ except = ! inv]t & track con/ruction1 etc4 ,ano!r modification ( ! p>allel longitud9al tr5*es me?od 0 us$ 9 ! con/ruction ( ! ,new ,york subway4 ,a n>r[ longitud9al tr5* 0 excavat$ on "o side ( ! /reet ne> ! sidewalk4 ,mean:ile ! pavem5t ( half ( ! /reet 0 remov$ & a wood5 plat=m ( heavy planks1 support$ by longitud9al beams :i* 7 buri$ 9 ! gr\nd1 0 sub/itut$4 ,!n small cuts und]nea? ! c> tracks 7 direct$ f ! side tr5* & heavy beams or ne$les 7 plac$ 9 ^! cuts1 :i* also rea*$ ! longitud9al beams ( ! wood5 plat=m4 ,! ne$les 7 w$g$ & block$ to ! c> track /ructure & ! beams4 ,!y 7 tempor>ily support$ by cribs built f und]nea? z ! excavation progress$4 ,:5 ! subgrade 0 rea*$1 v]tical & batt] po/s 7 ins]t$ to support ! ne$les1 ?us =m+ regul> timb] b5ts und]gr\nd4 ,9 ! space ?us left op5 ! subway 0 con/ruct$ to ! middle ( ! /reet4 ,:ile ! "w 0 go+ on z describ$1 ano!r longitud9al n>r[ tr5* 0 excavat$ at "s di/ance on ! o!r side ( ! /reet4 ,f ?is tr5*1 ! "w ( con/ruct+ ! o!r half ( ! subway 0 c>ri$ on 9 ! mann] j describ$4 ,aft] ! "w _h be5 complet$1 ! timb]s remov$1 ! voids fill$ 9 & ! pavem5t ( ! /reet re/or$1 ano!r equal section 0 attack$ on bo? sides ( ! /reet4 ,transv]se ,tr5*es4--,! transv]se tr5* or 8slice0 me?od ( op5-cut tunnel+ has be5 employ$ 9 "o "w1 ! ,bo/on ,subway4 ,?is me?od is describ$ 9 ! specifications = ! "w prep>$ by ! *ief eng9e]1 ,mr4 ,h4 ,a4 ,c>son1 ,m4 ,am4 ,soc4 ,c4 ,e41 z foll[s3-- 8,tr5*es ab\t #ab ft4 wide %all be excavat$ across ! /reet to z great a di/ance & dep? z is necess>y = ! con/ruction ( ! subway4 ,! top ( ?is excavation %all be bridg$ dur+ ! night by /rong beams & timb]+1 ^: upp] surface is flu% ) ! surface ( ! /reet4 ,^! beams %all be us$ to support ! railway tracks z well z ! ord9>y traffic4 ,9 ea* tr5* a small portion or slice ( ! subway %all be con/ruct$4 ,ea* slice ( ! subway ?us built is to be prop]ly jo9$ 9 due "t to ! contigu\s slices4 ,! contractor %all at all times h z _m slice-tr5*es 9 process ( excavation1 9 process ( be+ fill$ ) masonry1 & 9 process ( be+ back-fill$ ) e>? above ! complet$ masonry1 z is necess>y = ! ev5 & /eady progress ( ! "w t[>ds completion at ! "t nam$ 9 ! contract40 ,9 reg>d to ! success ( ?is me?od ,mr4 ,c>son1 9 8 f\r? annual report on ! ,bo/on ,subway "w1 says3 8,! me?od 0 su* t ! /reet railway tracks 7 n di/urb$ at all1 & ! :ole surface ( ! /reet1 if desir$1 0 left 9 daytime :olly free = ! normal traffic40 ,tunnels on ! ,surface4--,x occasionally happ5s :5 fill+-9 is to take place 9 ! future1 or :]e l&slides are liable to bury ! tracks1 t a railway tunnel has to be built on ! surface ( ! gr\nd4 ,9 su* cases ! con/ruction ( ! tunnel consi/s simply 9 build+ ! l9+ ( ! section on ! gr\nd surface ) j en\gh excavation to secure ! prop] grade & f\ndation4 ,g5]ally ! l9+ is f9i%$ on ! outside ) a wat]pro( coat+1 & is sometimes bank$ & p>tly cov]$ ) e>? to protect ! masonry f fall+ /ones & simil> %ocks f o!r causes4 ,a rec5t example ( tunnel con/ruction ( ?is "* 0 describ$ 9 8,eng9e]+ ,news0 ( ,sept4 #h1 #ahih4 ,9 con/ruct+ ! ,gold5 ,circle ,railroad1 9 ! ,cripple ,creek m9+ di/rict ( ,colorado1 ! l9e _h to be c>ri$ across a valley us$ z a dump+-gr\nd = ! refuse ( ! surr\nd+ m9es4 ,to protect ! l9e f ?is refuse1 ! eng9e] con/ruct$ a tunnel l9+ consi/+ ( successive /eel ribs1 fill$ betwe5 ) masonry4 ,conclud+ ,rem>ks4--,f ! fact t ! op5-cut me?od ( tunnel+ consi/s fir/ 9 excavat+ a cut1 & second 9 cov]+ ?is cut to =m an und]gr\nd passageway1 x has be5 nam$ ! 8cut-&-cov]0 me?od ( tunnel+4 ,! cut-&-cov] me?od ( tunnel+ is almo/ nev] employ$ else:]e ?an 9 cities1 or :]e ! surface ( ! gr\nd has to be re/or$ = ! accommodation ( traffic & bus9ess4 ,:5 x is n necess>y to re/ore ! orig9al surface1 z is usually ! case ) tunnels built 9 ! ord9>y c\rse ( railway "w1 x w\ld obvi\sly be absurd to d s except 9 extraord9>y cases4 ,9 a g5]al way1 !re=e1 x may be said t ! cut-&-cov] me?od ( con/ruction is conf9$ to ! build+ ( tunnels "u city /reets2 & ! discussion ( ?is k9d ( tunnels foll[s logically ! g5]al description ( ! op5-cut me?od ( tunnel+ :i* has be5 giv54 ,,tunnels ,,"u ,,city ,,/reets4 ,! ?ree mo/ common purposes ( tunnels "u city /reets are3 to provide = ! removal ( railway tracks f ! /reet surface1 & sep>ate ! /reet railway traffic f ! vehicul> & p$e/rian traffic2 to provide = rapid transit railways f ! bus9ess section to ! outly+ resid5ce di/ricts ( ! city2 & to provide conduits = sewage or subways = wat] & gas ma9s1 sew]s1 wires1 etc4 ,)9 rec5t ye>s ! greate/ works ( tunnel+ "u city /reets h be5 design$ & c>ri$ out to furni% improv$ transit facilities4 ,conditions ( ,"w4--,! con/ruction ( tunnels "u city /reets may be divid$ into two classes1 :i* may be briefly def9$ z %all[ tunnels & deep tunnels4 ,%all[ tunnels1 or ^? con/ruct$ at a small dep? b5ea? ! surface1 are usually built by "o ( ! cut-&-cov] me?ods2 deep tunnels1 or ^? built at a great dep?1 b5ea? ! surface are con/ruct$ by any ( ! v>i\s me?ods ( tunnel+ describ$ 9 ?is book1 ! *oice ( ! me?od dep5d+ ^u ! "* ( ! mat]ial p5etrat$1 & ! local conditions4 ,9 build+ tunnels "u city /reets ! fir/ duty ( ! eng9e] is to di/urb z little z possible ! v>i\s exi/+ /ructures & ! activities = :i* ^! /ructures & ! /reet are design$4 ,! "* ( ! difficulties enc\nt]$ 9 p]=m+ ?is duty w dep5d ^u ! dep? at :i* ! tunnel is driv54 ,9 con/ruct+ %all[ tunnels by ! cut-&-cov] me?od c>e has to be tak5 fir/ ( all n to di/urb ! /reet traffic any m ?an is absolutely necess>y4 ,?is condition precludes ! s+le tr5* me?od ( op5 cut tunnel+ 9 all places :]e ! /reet traffic is at all d5se1 & compels ! eng9e] to use ! me?ods employ$ 9 ,p>is & ,new ,york1 z previ\sly describ$1 or else ! transv]se tr5* or slice me?od employ$ 9 ! ,bo/on ,subway4 ,^! me?ods h to be modifi$ :5 ! "w is done on /reets hav+ und]gr\nd trolley & cable roads1 & 9 :i* are locat$ gas & wat] pipes1 conduits = wires1 etc4 ,:]e und]gr\nd trolley or cable railways are enc\nt]$1 a common mode ( proc$ure is to excavate p>allel side tr5*es = ! side walls1 & turn ! ro( ar* until x rea*es ! conduit c>ry+ ! cables or wires4 ,! e>? is !n remov$ f b5ea? ! conduit /ructure 9 small sections1 & ! ar* complet$ z ea* section is op5$4 ,z fa/ z ! ar* is complet$ ! conduit /ructure is support$ on x4 ,:]e pipes are enc\nt]$ !y may be support$ by means ( *a9s1 susp5d+ !m f heavy cross-beams1 or by means ( /rutt+1 or !y may be remov$ & rebuilt at a new level4 ,g5]ally ! conditions require a diff]5t solution ( ?is problem at diff]5t po9ts4 ,ano!r s]i\s difficulty ( tunnel+ "u city /reets arises f ! dang] ( di/urb+ ! f\ndations ( ! adjac5t build+s4 ,?is dang] exi/s only :]e ! dep? ( ! tunnel excavation ext5ds bel[ ! dep? ( ! build+ f\ndations1 & :]e ! mat]ial p5etrat$ is s(t gr\nd4 ,:]e ! tunnel p5etrates rock !re is no dang] ( di/urb+ ! build+ f\ndations4 ,to prev5t tr\ble ( ?is "* requires simply t ! excavation ( ! tunnel be s conduct$ t !re is no infl[ ( ! surr\nd+ mat]ial1 :i* may1 by caus+ a settlem5t ( ! neighbor+ mat]ial1 all[ ! f\ndations re/+ on x to s9k4 ,! ,baltimore ,belt tunnel1 describ$ 9 a prec$+ *apt]1 is an example ( ! me?od ( "w adopt$ 9 con/ruct+ a tunnel "u city /reets ?r\gh v s(t gr\nd4 ,?is may be class$ z a deep tunnel4 ,ano!r me?od ( deep tunnel+ "u city /reets is ! %ield me?od1 examples ( :i* are giv5 9 a succe$+ *apt]4 ,two notable examples ( cut-&-cov] me?ods ( tunnel+ are ! ,bo/on ,subway & ! ,new ,york ,rapid ,transit ,ry41 a description ( :i* foll[s4 ,bo/on ,subway4--,! ,bo/on ,subway may be def9$ z ! und]gr\nd t]m9al sy/em ( ! surface /reet railway sy/em ( ! city1 & z su* x comprises v>i\s bran*es1 loops1 & /ations4 ,! subway beg9s at ! ,public ,g>d5 on ,boyl/on ,/41 ne> ,*>les ,/41 & passes ) d\ble tracks "u ,boyl/on ,/4 to its int]section ) ,tremont ,/41 :]e x meets ! o!r d\ble-track bran*1 pass+ "u ,tremont ,/4 & beg9n+ at its int]section ) ,%awmut ,ave4 ,f _! int]section at ,tremont & ,boyl/on /reets ! two d\ble-track bran*es proce$ "u ,tremont ,/4 ) f\r tracks to ,scollay ,squ>e4 ,at ,scollay ,squ>e ! subway divides aga9 into two d\ble-track bran*es1 "o pass+ "u ,hanov] ,/41 & ! o!r "u ,wa%+ton ,/4 ,at ! int]section ( ,hanov] & ,wa%+ton /reets ! two d\ble-track bran*es comb9e aga9 into a f\r-track l9e1 :i* runs "u ,wa%+ton ,/4 to its t]m9us at ,haym>ket ,squ>e1 :]e x comes to ! surface by means ( an incl9e4 ,! subway1 !re=e1 has ?ree portals or entrances1 locat$ respectively at ,boyl/on ,/41 ,%awmut ,ave41 & ,haym>ket ,squ>e4 ,x also has five /ations & two loops1 ! =m] be+ locat$ at ,boyl/on ,/41 ,p>k ,/41 ,scollay ,squ>e1 ,adams ,squ>e1 & ,haym>ket ,squ>e1 & ! latt] at ,p>k ,/4 & ,adams ,squ>e4 ,! total l5g? ( ! subway is #aj1haj ft4 ,mat]ial ,p5etrat$4--,! mat]ial met ) 9 con/ruct+ ! subway 0 alluvial 9 "*1 ! l[] /rata be+ g5]ally compos$ ( blue clay & s&1 & ! upp] /rata ( m loose soil1 su* z loam1 oy/] %ells1 gravel1 & peat4 ,at _m po9ts ! mat]ial 0 s /able t ! walls ( ! excavation w\ld /& v]tical = "s "t aft] excavation4 ,surface wat] 0 enc\nt]$1 b g5]ally 9 small quantities1 except ne> ! ,boyl/on ,/4 portal1 :]e x 0 s pl5tiful z to cause "s tr\ble4 ,illu/ration3 ,,fig4 #aae4--,wide ,ar* ,section1 ,bo/on ,subway4 ,cross-,section4--,! subway be+ built = two tracks 9 "s places & = f\r tracks 9 o!r places1 x 0 necess>y to v>y ! =m & dim5sions ( ! cross-section4 ,! cross-sections actually adopt$ are ( ?ree types4 ,fig4 #aae %[s ! section kn[n z ! wide-ar* type1 9 :i* ! l9+ is solid masonry4 ,! second type 0 kn[n z ! d\ble-b>rel section1 & is %[n by ,fig4 #aaf4 ,! ?ird type ( section is %[n by ,fig4 #aag4 ,! l9+ consi/s ( /eel columns c>ry+ transv]se ro( gird]s1 ! ro( gird]s be+ fill$ betwe5 ) ar*es1 & ! wall columns hav+ concrete walls betwe5 !m4 ,! wide-ar* type & ! d\ble-b>rel type ( sections 7 employ$ 9 "s portions ( ! ,tremont ,/4 l9e1 :]e ! traffic 0 v d5se1 s9ce x 0 possible to con/ruct !m )\t op5+ ! /reet4 ,mu* ( ! wide-ar* l9e 0 con/ruct$ by ! use ( ! ro( %ield1 :i* is describ$ 9 ! succe$+ *apt] on ! %ield sy/em ( tunnel+4 ,illu/ration3 ,,fig4 #aaf4--;,d\ble-,b>rel ,section1 ,bo/on ,subway4 ,me?ods ( ,con/ruction4--,sev]al diff]5t me?ods 7 employ$ 9 con/ruct+ ! subway4 ,:]e ample space 0 available1 ! s+le wide tr5* me?od ( cut-&-cov] con/ruction 0 employ$1 ! e>? be+ remov$ z fa/ z excavat$4 ,9 ! /reets1 except :]e regul> tunnel+ 0 resort$ to1 ! p>allel tr5* or transv]se tr5* cut-&-cov] me?ods 7 employ$4 ,9 ! transv]se tr5* me?od1 tr5*es ab\t #ab ft4 wide 7 excavat$ across ! /reet1 _! l5g? be+ equal to ! extreme transv]se wid? ( ! tunnel l9+1 & _! dep? be+ equal to ! dep? ( ! tunnel floor4 ,^! tr5*es 7 begun dur+ ! night1 & imm$iately ro($ ov] ) a timb] plat=m flu% ) ! /reet surface4 ,"u ^! plat=ms ! excavation 0 complet$ & ! l9+ built4 ,z ea* tr5* or 8slice0 0 complet$1 ! /reet above x 0 re/or$ & ! plat=m recon/ruct$ ov] ! succe$+ tr5* or slice4 ,dur+ ! con/ruction ( ea* slice ! /reet traffic1 includ+ ! /reet c>s1 0 c>ri$ by ! timb] plat=m4 ,illu/ration3 ,,fig4 #aag4--;,f\r-,track ,rectangul> ,section1 ,bo/on ,subway4 ,illu/ration3 ,,fig4 #aah4--,section ,%[+ ,slice ,me?od ( ,con/ruction1 ,bo/on ,subway4 ,9 ! p>allel tr5* me?od1 %ort p>allel tr5*es 7 dug = ! opposite side walls1 & also = ! int]m$iate columns1 & completely ro($ ov] dur+ ! night4 ,"u ?is ro(+ ! masonry ( ! side walls & column f\ndations & ! columns !mselves 7 erect$4 ,:5 ! side walls & columns _h be5 erect$1 ! surface ( ! /reet betwe5 !m 0 remov$1 ! ro( beams laid1 & a plat=m cov]+ erect$1 z %[n by ,fig4 #aah4 ,?is ro(+ "w 0 also done at night4 ,! subsequ5t "w ( build+ ! ro( ar*es1 remov+ ! rema9d] ( ! e>?1 & con/ruct+ ! inv]t1 0 c>ri$ on und]nea? ! plat=m cov]+ :i* c>ri$ ! /reet traffic 9 ! meantime4 ,! successive repetition ( ! processes describ$ con/ruct$ ! subway4 ,:]e ! traffic 0 v d5se on ! /reet above1 tunnel+ 0 resort$ to4 ,= small portions ( ?is "w ! excavation 0 done 9 ! ord9>y way1 us+ timb] /rutt+1 b mu* ! great] portion ( ! tunnel "w 0 p]=m$ by means ( a ro( %ield4 ,9 ! latt] case1 ! side walls 7 fir/ built 9 small bottom side drifts & 7 fitt$ ) tracks on top to c>ry ! ro( %ield4 ,! con/ruction & op]ation ( ?is %ield are describ$ fully 9 ! succe$+ *apt] on ! %ield sy/em ( tunnel+4 ,masonry4--,! masonry ( ! incl9$ approa*es to ! subway consi/s simply ( two p>allel /one masonry reta9+ walls4 ,9 ! wide-ar* & d\ble-b>rel tunnel sections1 ! side walls are ( concrete & ! ro( ar*es are ( brick masonry4 ,9 ! o!r p>ts ( ! subway ! masonry consi/s ( brick jack ar*es sprung betwe5 ! ro( beams & cov]$ ) concrete1 ( concrete walls emb$d+ ! side columns1 & ( ! concrete inv]t & f\ndations = ! columns4 ,figs4 #aae to #aah inclusive %[ ! g5]al details ( ! masonry "w = ea* ( ! ?ree sections4 ,! inside ( ! l9+ masonry is pa9t$ ?r\gh\t ) :ite pa9t4 ,/ations4--,! design & con/ruction ( ! /ations = ! ,bo/on ,subway 7 made ! subjects ( consid]able ?\ght4 ,all ! /ations consi/ ( two isl& plat=ms ( artificial /one hav+ /airways lead+ to ! /reet above4 ,! plat=ms are made #a ft4 high] ?an ! rails4 ,! /ation /ructure itself is built ( /eel columns & ro( beams ) brick ro( ar*es & concrete side walls4 ,its int]ior is l9$ ) :ite enamel$ tiles4 ,! int]m$iate columns are cas$ ) wood1 & h circul> wood5 seats at _! bottoms4 ,ea* /airway is cov]$ by a light h\s+1 consi/+ ( a /eel framework ) a copp] cov]+ & an int]ior wood & tile f9i%4 ,v5tilation4--,! subway is v5tilat$ by means ( exhau/ fans locat$ 9 sev5 fan *amb]s1 "s ( :i* conta9 two fans1 & o!rs only "o fan4 ,ea* ( ! fans has a capacity ( f #cj1jjj to #cg1jjj cu4 ft4 ( air p] m9ute1 & is driv5 by electric motor1 tak+ curr5t f ! trolley wires4 ,?is sy/em ( v5tilation has work$ satisfactorily4 ,disposal ( ,ra9 ,wat]4--,! ra9 wat] :i* ent]s ! subway f ! incl9$ entrances1 toge!r ) t f leakage1 is lift$ f #ab ft4 to #ah ft4 by automatic electric pumps to ! city sew]s4 ,! subway has pump-wells at ! ,public ,g>d51 at ,eliot ,/41 ,adams ,squ>e1 & ,haym>ket ,squ>e4 ,9 ea* ( ^! wells are two v]tical subm]g$ c5trifugal pumps made entirely ( composition metal4 ,9 ea* *amb] above1 are two electric motors op]at+ ! pumps4 ,ea* motor is />t$ & /opp$ accord+ to ! height ( wat] by means ( a float & an automatic release />t+ box4 ,! floats are s plac$ t only "o pump is usually br\ght into use4 ,! o!r1 h[ev]1 comes into s]vice 9 case ! fir/ pump is out ( ord] or ! wat] ent]s m rapidly ?an "o pump c dispose ( x4 ,9 ! latt] case1 bo? motors cont9ue to run until ! same l[ level has be5 rea*$4 ,v little dampness except f atmosph]ic cond5sation is to be f\nd on ! int]ior walls or ro( ( ! subway1 al?\gh num]\s discolor$ pat*es1 caus$ by dampness & du/1 may be se5 on "s p>ts ( ! walls4 ,sub/antially all ( ! leakage comes ?r\gh ! small dra9s 9 ! inv]t lead+ f holl[s left 9 ! side walls4 ,c>eful measurem5t 0 tak5 at ! end ( an unusually wet season to det]m9e ! actual am\nt ( leakage1 & ! total am\nt = ! entire subway 0 f\nd to be ab\t #ha gallons p] m9ute4 ,e/imat$ ,quantities4--,! e/imat$ quantities ( mat]ial us$ 9 con/ruct+ ! subway 7 z foll[s3 ,excavation #cfi1dej cu4 yds4 ,concrete #ge1ffj ,brick #aa1aje ,/eel #h1aje tons ,granite #b1bhe cu4 yds4 ,piles #aag1ibe l94 ft4 ,ribb$ tiles #ab1ddj sq4 yds4 ,pla/] #hh1aij ,wat]pro(+ 7asphalt coat+7 #aag1ihj ,artificial /one #f1gij ,enamel$ brick #b1baj ,enamel$ tiles #b1hee ,co/ ( ! ,subway4--,! e/imat$ co/ ( ! subway made be=e ! "w 0 begun 0 approximately #d1jjj1jjj1 & ! co/ ( con/ruction did n exce$ #c1gjj1jjj4 ,?is includes v5tilat+ & pump *amb]s1 *anges ( wat] & gas pipes1 sew]s & o!r /ructures1 adm9i/ration1 eng9e]+1 int]e/ on bonds1 & all co/ :atsoev]4 ,divid+ ?is numb] by ! total l5g? we obta9 a co/ p] l9e> foot ( #cdb4cj4 ,new ,york ,rapid ,transit ,railway4--,! project ( an und]gr\nd rapid transit railway to run ! entire l5g? ( ,manhattan ,isl& 0 orig9at$ "s ye>s previ\s to #ahij4 ,9 #ahid1 h[ev]1 a ,rapid ,transit ,commission 0 appo9t$ to prep>e plans = su* a road1 & aft] a l>ge am\nt ( tr\ble & delay ?is commission aw>d$ ! contract = con/ruction to ,mr4 ,john ,b4 ,mc,donald ( ,new ,york ,city1 on ,jan4 #ae1 #aijj4 ,r\te4--,! road />ts f a loop :i* encircles ! ,city ,hall ,p>k4 ,)9 ?is loop ! tunnel con/ruction is two-track2 b :]e ! ma9 l9e leaves ! loop1 all f\r tracks come to ! same level1 & cont9ue side by side !reaft] except at ! po9ts :i* w be not$ z ! description proce$s4 ,proce$+ f ! loop1 ! f\r-track l9e passes "u ,c5t] & ,elm ,/reets4 ,x cont9ues "u ,lafayette ,place1 across ,a/or ,place & private prop]ty betwe5 ,a/or ,place & ,n9? ,/4 to ,f\r? ,ave4 ,! road !n passes "u ,f\r? & ,p>k ,av5ues until #db;d ,/4 is rea*$4 ,at ?is po9t ! l9e turns we/ along #db;d ,/41 :i* x foll[s to ,broadway4 ,x turns nor?w>d aga9 "u ,broadway to ! b\lev>d1 cross+ ! ,circle at #ei? ,/4 ,! road !n foll[s ! b\lev>d until #ig? ,/4 is rea*$1 :]e ! f\r-track l9e is sep>at$ into two d\ble-track l9es4 ,at a suitable po9t nor? ( #if? ,/4 ! outside tracks rise s z to p]mit ! inside tracks1 on rea*+ a po9t ne> #ajc;d ,/41 to curve to ! "r1 pass+ "u ! nor?-b\nd track1 & to cont9ue !nce across & "u private prop]ty to #ajd? ,/4 ,f !re ! two-track tunnel goes "u #ajd? ,/4 & ,c5tral ,p>k to #aaj? ,/41 ne> ,l5ox ,ave42 !nce "u ,l5ox ,ave to a po9t ne> #adb;d ,/42 !nce across & "u private prop]ty & ! int]v5+ /reets to ! ,h>lem ,riv]4 ,! road passes "u ! ,h>lem ,riv] & across & "u private prop]ty to #adi? ,/41 :i* /reet x foll[s to ,?ird ,ave41 & !n passes "u ,we/*e/] ,ave41 :]e1 at a conv5i5t po9t1 ! tracks em]ge f ! tunnel & are c>ri$ on a viaduct along & ov] ,we/*e/] ,ave41 ,s\!rn ,b\lev>d1 & ,bo/on ,road to ,bronx ,p>k4 ,?is portion ( ! l9e1 f #if? ,/4 to ,bronx ,p>k1 is kn[n z ! ,ea/ ,side ,l9e4 ,f ! nor!rn side ( #if? ,/4 ! outside tracks rise & aft] cross+ ov] ! inside tracks !y are br\ght toge!r on a location "u ! c5t] l9e ( ! /reet & proce$ along "u ! b\lev>d to a po9t betwe5 #abb;d & #abc;d ,/reets4 ,at ?is po9t ! tracks comm5ce to em]ge f ! tunnel1 & are c>ri$ on a viaduct along & ov] ! b\lev>d at a po9t betwe5 #acd? & #ace? ,/reets1 :]e !y aga9 pass into ! tunnel "u & along ! b\lev>d & ,elev5? ,ave4 to a po9t ab\t #acej ft4 nor? ( ! c5t] l9e ( #aij? ,/4 ,!re ! tracks aga9 em]ge f ! tunnel1 & are c>ri$ on a viaduct across & ov] private prop]ty to ,elwood ,/41 & ov] & along ,elwood ,/4 to ,k+sbridge ,/4 to ,k+sbridge ,ave41 private prop]ty1 ! ,h>lem ,%ip ,canal & ,spuyt5 ,duyvil ,creek1 private prop]ty1 ,riv]dale ,ave41 & ,broadway to a t]m9us ne> ,van ,cortl& ,p>k4 ,t portion ( ! l9e f #if? ,/4 to ! above-m5tion$ t]m9us at ,van ,cortl& ,p>k is kn[n z ! ,we/ ,side ,l9e4 ,! total l5g? ( ! rapid transit road1 includ+ ! p>ts above & bel[ ! surface gr\nd ( ! /reets1 z well z bo? ! ,ea/ & ,we/ ,side ,l9es1 is ab\t #bb miles4 ,mat]ial ,p5etrat$4--,! soil ?r\gh :i* ! road 0 excavat$ 0 a v>i$ "o4 ,! l[] portion ( ! road1 or ! "p includ+ ! loop up to ne>ly ,f\r? ,/41 0 excavat$ ?r\gh loose soil1 b f ,f\r? ,/4 to ! ends x 0 excavat$ 9 rock4 ,! loose soil =m+ ! s\!rn "p ( ,manhattan ,isl& is *iefly compos$ ( clay1 s&1 & old rubbi%--a soil v easy to excavate4 ,wat] 0 met at "s po9ts1 b n 9 su* quantities z to be a s]i\s inconv5i5ce4 ,f ,f\r? ,/4 to ! ends ( bo? ! ea/ & we/ side l9es1 ! soil 0 *iefly compos$ ( rock ( gneissoid & mica-s*i/ose "*1 ^! rocks prevail+ ne>ly ?r\gh\t ! :ole ( ,manhattan ,isl&4 ,! rock1 z a rule1 0 n compact1 b full ( seams & fissures1 & at _m po9ts x 0 f\nd dis9tegrat$ & alt]nat$ ) /rata ( loose soils1 & ev5 pockets ( quicks& 7 met ) along ! l9e ( ! road4 ,cross-,sections4--,! section ( ! und]gr\nd road is ( ?ree diff]5t types1--! rectangul>1 ! b>rel-vault1 & ! circul>4 ,! rectangul> section4 ,fig4 #aai1 is us$ = ! great] "p ( ! road1 ( :i* a portion is = f\r tracks & a portion = two tracks4 ,! dim5sions adopt$ = ! f\r tracks are #ej #ac ft41 & = ! d\ble tracks #be #ac ft4 ,! b>rel-vault section1 compos$ ( a polyc5tric ar*1 hav+ ! flatte/ curve at ! cr[n1 has be5 adopt$ = ! tunnels "u ,p>k ,av5ue--:ile ! semicircul> ar* is us$ = all ! o!r portions ( ! road to be tunnel$4 ,! circul> section ( #ae-;ft4 diamet] is us$ "u ! ,h>lem ,riv]1 & be+ = s+le track1 two p>allel tunnels 7 built side by side4 ,illu/ration3 ,,fig4 #aai4--;,d\ble-,track ,section1 ,new ,york ,rapid ,transit ,railway4 ,! ma9 l9e f ! ,city ,hall loop to ab\t #ajb;d ,/4 consi/s ( f\r tracks built side by side 9 "o conduit1 except = t portion "u ! pres5t ,f\r? ,ave4 tunnel :]e two p>allel d\ble-track tunnels are employ$4 ,! ,we/ ,side ,l9e w consi/ ( d\ble tracks laid 9 "o conduit1 except across ,manhattan ,/4 & beyond #aij? ,/41 :]e x is c>ri$ on an elevat$ /ructure4 ,! ,ea/ ,side ,l9e consi/s ( a d\ble-track tunnel driv5 f #ajb;d ,/41 & ! b\lev>d "u ,c5tral ,p>k to #aaj? ,/4 & ,l5ox ,ave41 & two p>allel circul> tunnels excavat$ "u ! ,h>lem ,riv]1--! o!r portions ( ! road be+ d\ble-track1 subway & elevat$ /ructure4 ,me?ods ( ,excavation4--,bo? ! d\ble-& f\r-track subway 7 built by us+ ! diff]5t v>ieties ( ! cut-&-cov] me?od4 ,! s+le wide-tr5* me?od 0 us$ = ! con/ruction ( ! d\ble-track l9e & also = ! con/ruction ( ! f\r-track l9e :]e ! local conditions all[$ x4 ,! s+le n>r[-tr5* me?od 0 us$ = ! con/ruction ( ! f\r-track subway at #db;d ,/41 to meet ) ! peculi> conditions ( ! traffic4 ,almo/ ! total l5g? ( ! f\r-track l9e ( ! subway 0 built by means ( ! two p>allel side tr5*es4 ,! slice me?od1 s successfully employ$ 9 ! ,bo/on ,subway1 0 us$ only on #db;d ,/4 we/ ( #f? ,av5ue4 ,l9+4--,! l9+ ( ! subway is ( concrete1 c>ri$ by a framework ( /eel4 ,! floor consi/s ( a f\ndation lay] ( concrete at lea/ eight in*es ?ick on good f\ndation1 b ?ick]1 accord+ to conditions1 :]e ! f\ndation is bad4 ,on top ( ?is is plac$ ano!r lay] ( concrete1 ) a lay] ( wat]pro(+ betwe5 ! two4 ,9 ?is top lay] are set ! /one p$e/als = ! /eel columns1 & ! memb]s mak+ up ! tracks4 ,9 ! f\r-track subway1 ! /eel framework consi/s ( transv]se b5ts ( columns1 & ,i-beams spac$ ab\t five feet ap>t along ! tunnel4 ,! ?ree int]ior columns ( ea* b5t are built-up bulb-angle & plate columns ( ,h-section4 ,! wall columns are ,i-beams1 z are also ! ro( beams2 betwe5 ! ,i-beams1 wall columns1 & ro( beams !re is a concrete fill+1 s t ! ro( ( ! subway w be made up ( concrete ar*es re/+ on ! flanges ( ! ,i-beams ( ! ro(4 ,! concrete us$ is ( "o "p ,portl& cem5t1 two p>ts s&1 & f\r p>ts brok5 /ones4 ,! d\ble-track subway is built 9 ! same way1 except t only "o column is plac$ betwe5 ! tracks = ! support ( ! ro(4 ,all ! concrete masonry ( ! ro(1 f\ndations1 & side walls conta9s a lay] ( wat]pro(+1 s z to keep p]fectly dry ! und]gr\nd road1 & prev5t ! p]colation ( wat]4 ,?is wat]pro(+ is made up z foll[s3 ,on ! l[e/ /ratum ( concrete1 ^: surface is made z smoo? z possible1 a lay] ( hot asphalt is spread4 ,on ?is asphalt are imm$iately laid %eets or rolls ( felt2 ano!r lay] ( hot asphalt is !n spread ov] ! felt1 & !n ano!r lay] ( felt laid1 & s on1 until no less ?an two1 & no m ?an six1 lay]s ( felt are laid1 ) ! felt betwe5 lay]s ( asphalt4 ,on top ( ! upp] surface ( asphalt ! rema9d] ( ! concrete is put 9 place s z to rea* ! requir$ ?ickness ( ! concrete wall4 ,illu/ration3 ,,fig4 #abj4--,p>k ,av5ue ,deep ,tunnel ,con/ruction1 ,new ,york ,rapid ,transit ,railway4 ,tunnels4--,:5 ! di/ance betwe5 ! ro( ( ! propos$ /ructure & ! /reet 0 #bj ft4 or ov]1 ! ,/&>d ,subway con/ruction 0 replac$ by tunnels4 ,?ree important tunnels h be5 con/ruct$ along ! l9e ( ! ,new ,york ,rapid ,transit & ^! are locat$ betwe5 #cc;d & #db;d ,/reets on ,p>k ,ave41 "u ,c5tral ,p>k nor!a/ ( #ajd? ,/4 & "u ,broadway nor? ( #aeb;d ,/4 ,! ,p>k ,ave4 con/ruction 7,fig4 #abj7 consi/s ( two p>allel d\ble-track tunnels1 locat$ on ea* side ( ! /reet1 & ab\t #aj ft4 bel[ ! pres5t tunnel4 ,! soil be+ compos$ ( good rock1 ! tunnels 7 driv5 by a wide head+1 & "o b5*1 s9ce no /rutt+ 0 requir$1 & ! masonry l9+1 ev5 ( ! ro(1 0 left f> beh9d ! front ( ! excavation4 ,! masonry l9+ consi/s ( concrete walls & brick ar*es4 ,! tunnels "u ,c5tral ,p>k & "u ,broadway be+ driv5 ?r\gh a simil> rock1 ! same me?od ( excavation & ! same mann] ( l9+ 0 us$4 ,! tunnel "u ! ,h>lem ,riv] 0 driv5 ?r\gh s(t gr\nd2 & x 0 con/ruct$ z a subm>9e tunnel1 accord+ to ! caisson process4 ,! tunnels 7 l9$ ) iron made up ( segm5ts1 ) radial & circumf]5tial flanges4 ,concrete 0 plac$ inside & flu% ) ! flanges4 ,illu/ration3 ,,fig4 #aba4--;,h>lem ,riv] ,tunnel1 ,new ,york ,rapid ,transit ,railway4 ,! tracks1 bo? 9 ! subway & tunnels1 are an intimate "p ( ! concrete floor+4 ,! rail re/s on a cont9u\s be>+ ( wood5 blocks1 laid ) ! gra9 runn+ transv]sely ) respect to ! l9e ( ! rail1 & held 9 place by two *annel iron gu>d rails4 ,! gu>d rails are bolt$ to metal cross-ties emb$d$ 9 ! concrete4 ,viaduct4--,a consid]able portion ( ! d\ble-track bran* l9es nor? ( #ajc;d ,/4 is viaduct1 or elevat$ /ructure4 ,! viaduct con/ruction on ! ,we/ ,side ,l9e ext5ds1 includ+ approa*es1 f #abb;d ,/4 to v ne> #ace? ,/4 ,( ?is di/ance1 #bjah ft4 #h ins4 are viaduct prop]1 consi/+ ( plate gird] spans c>ri$ by tre/le b5ts at ! ends1 & by tre/le t[]s = ! c5tral portion4 ,! columns ( ! b5ts & t[]s are built-up bulb-angle & plate columns ( ,h-section ( ! same =m z ^? us$ 9 ! b5ts inside ! subway4 ,! approa*es prop] are built ( masonry4 ,! elevat$ l9e prop] consi/s ( plate gird] spans1 support$ on plate cross gird]s c>ri$ by columns4 ,/ations4--,_m /ations are built along ! l9e4 ,^! are locat$ on ea* side ( ! /reet4 ,! entrances at ! /ations consi/ ( iron framework1 ) glass ro(s cov]+ ! desc5d+ /airways4 ,! passageways lead+ d[n are wall$ ) :ite enamel$ bricks & wa9scot$ ) slabs ( m>ble4 ,! /ations = ! local tra9s are locat$ on ea* side ( ! road close to ! walls1 s9ce ! outside tracks are res]v$ = ! local tra9s1 :ile ! middle ones are res]v$ = ! expresses4 ,! few /ations = ! express tra9s are locat$ betwe5 ! middle & outside tracks4 ,/ations are provid$ ) all ! conv5i5ces requir$1 hav+ toilet rooms1 news /&s1 b5*es1 etc41 & are light$ day & night by num]\s arc lamps4 ,g5]al4--,! contractor complet$ ! "w 9 f\r ye>s4 ,no difficulty 0 enc\nt]$ 9 do+ ?is1 s9ce ! great ext5sion ( ! road & ! great wid? ( ! av5ues "u :i* x runs all[$ "w all along ! l9e at ! same "t4 ,! "w1 briefly summ>iz$1 comprises ! foll[+ items3-- ,l5g? ( all sections1 ft4 #aji1egj ,total excavation ( e>?1 cu4 yds4 #a1gjj1bbh ,e>? to be fill$ back1 cu4 yds4 #ggc1jic ,rock excavat$1 cu4 yds4 #iba1abh ,rock tunnel$1 cu4 yds4 #cfh1fjf ,/eel us$ 9 /ructure1 tons #fe1jdd ,ca/ iron us$1 tons #g1ija ,concrete1 cu4 yds4 #dhi1abb ,brick1 cu4 yds4 #ah1eai ,wat]pro(+1 sq4 yds4 #gge1gie ,vault lights1 sq4 yds4 #f1fdj ,local /ations1 numb] #dc ,express /ations1 numb] #e ,/ation elevators1 numb] #aj ,track total1 l94 ft4 #cje1chj und]gr\nd1 l94 ft4 #bde1ead elevat$1 l94 ft4 #ei1gff ,9 addition to ! con/ruction ( ! railway itself1 x 0 necess>y to con/ruct or recon/ruct c]ta9 sew]s1 & to adju/1 readju/1 & ma9ta9 /reet railway l9es1 wat] pipes1 subways1 & o!r surface & subsurface /ructures1 & to relay /reet pavem5ts4 ,! total co/ ( ! "w1 accord+ to ! contract sign$ by ,mr4 ,mc,donald1 0 #ce1jjj1jjj4 ,divid+ ?is am\nt by ! total l5g? ( ! road1 :i* is #aji1egj l9eal feet1 we h ! unit co/ a l9eal foot #cae1 or a little less ?an unit ( co/ ( ! ,bo/on ,subway1 :i* 0 #cdb p] l9eal foot4 ,! road belongs to ! city4 ,! contractor acts z an ag5t = ! city 9 c>ry+ out ! "w1 & he is ! leas] ( ! road = fifty ye>s4 ,! "w 0 paid = z soon z ! v>i\s p>ts ( ! road 7 complet$1 & ! money 0 obta9$ f an issue ( city bonds4 ,dur+ ! fifty ye>s' lease ! contractor w pay ! int]e/ plus #a ( ! face value ( ! bonds4 ,?is #a goes to ! s9k+-fund1 :i* )9 ! fifty ye>s at comp\nd int]e/ =ms ! total sum requir$ = ! r$emption ( bonds4 ,?is fir/ ,new ,york ,subway has be5 ext5d$ to ,brooklyn1 & m l9es w be built s z to =m a complete und]gr\nd railway sy/em to accommodate ! ev]-increas+ travel+ cr[d ( ! ,am]ican metropolis4 ,no new me?od ( con/ruction has be5 devis$ yet4 ,! only v>iation f ! illu/rat$ me?ods has be5 :]e ! subway is built und]nea? ! ,elevat$ ,road :i* _h to be /rongly support$ dur+ ! con/ruction ( ! subway4 ,?is has be5 done 9 two diff]5t ways1 ei!r by support+ ! columns ( ! ,elevat$ ,road by means ( two wood5 ,a-frames abutt+ at ! top & leav+ a l>ge space close to ! foot ( ! column :]e a pit 0 excavat$ to ! requir$ dep? ( ! subway1 or by atta*+ ! columns to long iron gird]s plac$ longitud9ally & re/+ ) bo? ends 9 firm soil4 ,,*apt] ,,xvii4 ,,subm>9e ,,tunnel+3 ,,g5]al ,,discussion4--,,! ,,sev]n ,,tunnel4 ,,g5]al ,,discussion4 ,subm>9e tunnels1 or tunnels excavat$ "u ! b$s ( riv]s1 lakes1 etc41 h be5 con/ruct$ 9 l>ge numb]s dur+ ! la/ qu>t] ( a c5tury1 & ! projects = su* tunnels1 :i* h n yet be5 c>ri$ to completion1 are /ill m num]\s4 ,among ! m notable complet$ works ( ?is "* may be not$ ! tunnel "u ! ,riv] ,sev]n & ^? "u ! ,riv] ,?ames 9 ,engl&1 ! "o "u ! ,riv] ,se9e 9 ,france1 ^? "u ! ,/4 ,clair1 ,detroit1 ,hudson1 ,h>lem & ,ea/ ,riv]s1 & ! "o "u ! ,bo/on ,h>bor = railways1 t "u ! ,ea/ ,riv] = gas ma9s1 t "u ,dor*e/] ,bay1 ,bo/on1 = sewage1 & ^? "u ,lakes ,mi*igan & ,erie = ! wat] supply ( ,milwaukee1 ,*icago1 ,buffalo1 & ,clevel& 9 ,am]ica4 ,= ! details ( ! v>i\s project$ subm>9e tunnels ( note1 :i* include tunnels "u ! ,engli% & ,iri% ,*annels1 "u ! ,/raits ( ,gibralt>1 "u ! s\nd betwe5 ,cop5hag5 9 ,d5m>k & ,malm 9 ,sw$51 "u ! ,mess9a ,/raits betwe5 ,italy & ,sicily1 & "u ! ,/raits ( ,nor?umb]l& betwe5 ,new ,brunswick & ,pr9ce ,edw>d ,isl&1 & ^? connect+ ! v>i\s isl&s ( ! ,/raits ( ,behr+1 ! read] is ref]r$ to ! p]iodical lit]ature ( ! la/ few ye>s4 ,previ\s to attempt+ ! driv+ ( a subm>9e tunnel x is necess>y to asc]ta9 ! "* ( ! mat]ial x w p5etrate4 ,?is fact is g5]ally det]m9$ by mak+ diamond-drill bor+s along ! l9e1 & ! object ( asc]ta9+ x is to det]m9e ! me?od ( excavation to be adopt$4 ,if ! mat]ial is p]meable & ! tunnel mu/ pass at a small dep? bel[ ! riv] b$1 a me?od w h to be adopt$ :i* provides = h&l+ ! difficulty ( infl[+ wat]4 ,if1 on ! o!r h&1 ! tunnel passes ?r\gh imp]meable mat]ial at a great dep?1 !re w be no unusual tr\ble f wat]1 & almo/ any ( ! ord9>y me?ods ( tunnel+ su* mat]ials may be employ$4 ,%all[ subm>9e tunnels ?r\gh p]meable mat]ial are usually driv5 by ! %ield me?od or by ! compress$ air me?od1 or by a me?od :i* is a comb9ation ( ! fir/ & second4 ,x is n an uncommon exp]i5ce = a subm>9e tunnel to />t out 9 firm soil & unexpect$ly to f9d t ?is mat]ial becomes s(t & trea*]\s z ! "w proce$s1 or t x is int]sect$ by /rata ( s(t mat]ial4 ,! me?od ( deal+ ) ?is condition w v>y ) ! circum/ances1 b g5]ally if any consid]able am\nt ( s(t mat]ial has to be p5etrat$1 or if ! infl[ ( wat] is v l>ge1 ! firm-gr\nd sy/em ( "w is *ang$ to "o ( ! me?ods employ$ = excavat+ s(t-gr\nd subm>9e tunnels4 ,! ,milwaukee wat] supply tunnel1 describ$ else:]e1 is a notable example ( subm>9e tunnels1 began 9 firm mat]ial :i* unexpect$ly develop$ a trea*]\s "* aft] ! "w _h proce$$ "s di/ance4 ,occasionally ! task ( build+ a subm>9e tunnel 9 ! riv] b$ arises4 ,9 su* cases ! tunnel is usually built by means ( c(f]dams 9 %all[ wat]1 & by means ( caissons 9 deep wat]4 ,subm>9e tunnels "u riv]s are usually built ) a desc5d+ grade f ea* end :i* t]m9ates 9 a level middle position1 ! longitud9al pr(ile ( ! tunnel correspond+ to ! transv]se pr(ile ( ! riv] bottom4 ,:]e1 h[ev]1 su* tunnels pass "u ! wat] ) "o end subm]g$1 & ! o!r end ris+ to l& l ! wat] supply tunnels ( ,*icago1 ,milwaukee1 & ,clevel&1 ! longitud9al pr(ile is commonly level1 or else desc5ds f ! %ore to a level position rea*+ out "u ! wat]4 ,! dra9age ( subm>9e tunnels dur+ con/ruction is "o ( ! mo/ s]i\s problems ) :i* ! eng9e] has to deal 9 su* works4 ,?is arises f ! fact t1 s9ce ! entrances ( ! tunnel are high] ?an ! o!r p>ts1 all ( ! seepage wat] rema9s 9 ! tunnel unless pump$ out1 & f ! possibility ( enc\nt]+ faults or p]meable /rata1 :i* rea* to ! /ream b$ & give access to wat] 9 great] or less quantities4 ,g5]ally1 !re=e1 ! excavation is conduct$ 9 su* a mann] t ! infl[+ wat] is l$ directly to sumps4 ,to dra9 ^! sumps pump+ /ations are necess>y at ! %ore %afts1 & !y %\ld h ample capacity to h&le ! ord9>y am\nt ( seepage1 & en\gh surplus capacity to meet probable increases 9 ! infl[4 ,= extraord9>y em]g5cies ?is plant may h to be greatly enl>g$1 b x is n usual to provide = ^! at ! outset unless _! likelihood is obvi\s f ! />t4 ,! "* & size ( ! pump+ plants us$ 9 con/ruct+ a numb] ( well-kn[n tunnels are describ$ 9 ,*apt] ,,xii4 ,9 ?is book subm>9e tunnels w be classifi$ z foll[s3 7#a7 ,tunnels 9 rock or v compact soils1 :i* are driv5 by any ( ! ord9>y me?ods ( tunnel+ simil> mat]ials on l&2 7#b7 tunnels 9 loose soils1 :i* may be driv51 7a7 by compress$ air1 7b7 by %ields1 or 7c7 by %ields & compress$ air comb9$2 7#c7 tunnels on ! riv] b$1 :i* are con/ruct$1 7a7 by c(f]dams1 or 7b7 by caissons4 ,to illu/rate tunnels ( ! fir/ class1 ! ,riv] ,sev]n tunnel 9 ,engl& has be5 select$2 to illu/rate ^? ( ! second class1 ! sev]al tunnels discuss$ 9 ! *apt] on ! %ield sy/em ( tunnel+ & ! ,milwaukee tunnel is suffici5t2 to illu/rate ^? ( ! ?ird class1 ! ,van ,bur5 ,/reet tunnel 9 ,*icago1 ! ,h>lem1 ! ,se9e & ! ,detroit ,riv] tunnels are select$4 ,,! ,,sev]n ,,tunnel4 ,! ,sev]n tunnel1 :i* c>ries ! ,great ,we/]n ,railway ( ,engl&1 b5ea? ! e/u>y ( a l>ge riv]1 is #d miles #fdb y>ds long4 ,x p5etrates /rata ( conglom]ate1 lime/one1 c>bonif]\s b$s1 m>l1 gravel1 & s& at a m9imum dep? ( #dd ft4 bel[ ! deepe/ portion ( ! e/u>y b$4 ,! foll[+ description ( ! "w is ab/ract$ f a pap] by ,mr4 ,l4 ,f4 ,v]non-,h>c\rt4#ab #ab ,proce$+s ,in/4 ,c4 ,e41 vol4 cxxi4 ,! fir/ "w 0 ! s9k+ ( a %aft1 #ae ft4 9 diamet]1 l9$ ) brickwork1 on ! ,monm\?%ire bank ( ! ,sev]n1 #bjj ft4 deep4 ,aft] ! ,monm\?%ire %aft _h be5 sunk1 a head+ #g ft4 squ>e 0 driv5 "u ! riv]1 ris+ ) a gradi5t ( #a 9 #ejj f ! %aft on ! ,monm\?%ire %ore1 s z to dra9 ! l[e/ "p ( ! tunnel4 ,ne> to ! fir/1 a second %aft 0 sunk & tubb$ ) iron1 9 :i* ! pumps 7 plac$ = remov+ ! wat] f ! tunnel works1 connection be+ made by a cross-head+ ) ! head+ f ! fir/ %aft4 ,!re 0 also a %aft on ! ,gl\ce/]%ire %ore2 & two %afts inl& f ! fir/ on ! ,monm\?%ire side1 to exp$ite ! con/ruction ( ! tunnel4 ,head+s 7 !n driv5 9 bo? directions along ! l9e ( ! tunnel1 f ! f\r %afts2 & ! dra9age head+ f ! old %aft 0 cont9u$1 9 ! l9e ( ! tunnel1 "u ! deep *annel ( ! e/u>y1 & up ! asc5d+ gradi5t t[>ds ! ,gl\ce/]%ire %ore1 till1 9 ,octob]1 #ahgi1 x _h rea*$ to )9 ab\t #acj y>ds ( ! end ( ! desc5d+ head+ f ! ,gl\ce/]%ire %aft4 ,dur+ ?is p]iod1 ?\gh ! "w _h progress$ sl[ly1 no l>ge quantity ( wat] _h be5 met ) 9 any ( ! head+s1 9 spite ( _! already ext5d+ "u almo/ ! :ole wid? ( ! e/u>y4 ,on ,octob] #ah1 #ahhi1 h[ev]1 a great spr+ 0 tapp$ by ! head+ :i* 0 be+ driv5 l&w>ds f ! old %aft1 ab\t #dj ft4 above ! level ( ! dra9age head+2 & ! wat] p\r$ out f ?is l& spr+ 9 su* quantity t1 fl[+ along ! head+1 fall+ d[n ! old %aft1 & ?us f9d+ its way into ! dra9age head+ & ! long head+ ( ! tunnel "u ! e/u>y 9 connection ) x1 x flood$ ! :ole ( ! work+s 9 communication ) ! old %aft1 :i* x also fill$ )9 tw5ty-f\r h\rs f ! pi]c+ ( ! spr+4 ,to obta9 increas$ security aga9/ any influx ( wat] f ! deep *annel ( ! e/u>y into ! tunnel1 ! propos$ level portion ( ! tunnel1 r m ?an a furlong long "u ?is "p1 0 l[]$ #ae ft4 by increas+ ! desc5d+ gradi5t on ! ,monm\?%ire side f #a 9 #ajj to #a 9 #ij1 & l[]+ ! propos$ rail level on ! ,gl\ce/]%ire side #ae ft4 ?r\gh\t ! asc5t1 s z n to increase ! gradi5t ( #a 9 #ajj aga9/ ! load4 ,a new %aft1 #ah ft4 9 diamet]1 0 sunk slightly ne>] ! e/u>y on ! ,monm\?%ire %ore ?an ! old "o2 two %afts also 7 sunk on ! l& side ( ! great spr+ = pump+ purposes2 & additional pump+ ma*9]y 0 erect$4 ,! fl[ f ! spr+ into ! old %aft 0 arre/$ by a %ield ( oak fix$ across ! head+2 & at la/1 aft] num]\s failures & breakd[ns ( ! pumps1 ! head+s 7 cle>$ ( wat]1 aft] a div]1 suppli$ ) a knapsack ( compress$ oxyg51 _h clos$ a door 9 ! long head+ "u ! e/u>y2 & ! works 7 resum$ ne>ly f\rte5 mon?s aft] ! flood+ occurr$4 ,! great spr+ 0 !n %ut (f f ! work+s by a wall across ! head+ lead+ to ! old %aft2 &1 ow+ to ! l[]+ ( ! level ( ! tunnel1 a new dra9age head+ _h to be driv5 f ! bottom ( ! new %aft at a l[] level1 :i* 0 made #e ft4 9 diamet]1 & l9$ ) brickwork1 :il/ ! old dra9age head+ 0 enl>g$ to #i ft4 9 diamet]1 & l9$ ) brickwork1 s z to aid 9 ! p]man5t v5tilation ( ! tunnel4 ,! l[]+ ( ! level1 moreov]1 conv]t$ ! bottom tunnel head+s into top head+s1 s t along m ?an a mile ( ! tunnel ! semicircul> ar*1 #bf ft4 9 diamet]1 0 built fir/1 & !n1 aft] l[]+ ! head+s1 ! inv]t 0 laid & ! side walls 7 built up4 ,bottom head+s 7 driv5 along ! rema9d] ( ! tunnel1 & ! "w 0 exp$it$ by means ( break-ups4 ,v5tilation 0 effect$ 9 ! works by a fan #ah in*es 9 diamet] & #g ft4 wide1 fix$ at ! top ( ! new deep %aft2 ! rock 0 bor$ by drills work$ by compress$ air2 ! bla/+ 0 ev5tually effect$ exclusively by tonite1 ow+ to its be+ fre] f delet]i\s fumes ?an any o!r explosive2 & ! work+s 7 light$ by ,swan & ,bru% electric lamps4 ,! tunnel is l9$ ?r\gh\t ) vitrifi$ brickwork1 betwe5 #b ft4 to #c ft4 ?ick1 set 9 cem5t1 & has an inv]t #a ft4 to #c ft4 9 ?ickness2 ! l9+ 0 comm5c$ t[>ds ! end ( #ahhj1 ! head+s "u ! riv] 7 jo9$ 9 ,septemb]1 #ahha1 & ! la/ l5g? ( ! tunnel1 across ! l9e ( ! great spr+1 0 complet$ 9 ,april1 #ahhe4 ,wat] came 9 f ! riv] ?r\gh a hole 9 a pool ( ! e/u>y1 close to ! ,gl\ce/]%ire %ore1 9 ,april1 #ahha1 dur+ ! l9+ ( a portion ( ! tunnel1 b =tunately be=e ! head+s 7 jo9$4 ,?is influx 0 /opp$ by all[+ ! wat] to rise 9 ! tunnel to tide-level1 to prev5t ! enl>gem5t ( ! hole1 :i* 0 !n fill$ up at l[ wat] ) clay1 weight$ on ! top ) clay 9 bags4 ,! great spr+ broke out aga9 9 ,octob]1 #ahhc1 & flood$ ! works a second "t2 b )9 f\r weeks ! wat] _h be5 pump$ out & ! spr+ aga9 imprison$4 ,dur+ ?is p]iod an exceptionally high tide1 rais$ /ill high] by a s\?we/]ly gale1 inundat$ ! l[-ly+ l& on ! ,monm\?%ire side ( ! e/u>y1 &1 fl[+ d[n "o ( ! inl& %afts1 flood$ a section ( ! tunnel1 b ! pumps remov$ ?is wat] )9 a week4 ,9 ord] to con/ruct ! portion ( tunnel trav]s+ ! l9e ( ! great spr+1 ! wat] 0 div]t$ into a side head+ bel[ ! level ( ! tunnel1 lead+ to ! old %aft1 :5ce x 0 pump$1 & ! fissure bel[ ! tunnel 0 fill$ ) concrete1 ov] :i* ! inv]t 0 built4 ,an attempt to imprison ! spr+1 on ! completion ( ?is l5g? ( tunnel1 hav+ result$ 9 impos+ an excessive pressure on ! brickwork1 lead+ to fractures & leakage1 a %aft1 #bi ft4 9 diamet]1 0 sunk at ! side ( ! tunnel at ?is po9t 9 #ahhf1 & pumps 7 erect$ p[]ful en\gh to deal ) ! entire fl[ ( ! spr+4 ,! tunnel 0 op5$ = traffic 9 ,decemb]1 #ahhf1 & gives access to a d\ble l9e ( railway1 connect+ ! l9es conv]g+ to ,bri/ol ) ! ,s\? ,wales railway & ! we/]n l9es4 ,! pump+ p[] provid$ at ! %aft connect$ ) ! great spr+1 & at f\r o!r %afts1 is capable ( rais+ #ff1jjj1jjj gallons ( wat] p] day1 ! maximum am\nt pump$ f ! tunnel be+ #cj1jjj1jjj gallons a day4 ,! v5tilation ( ! tunnel is effect$ by fans plac$ 9 ! two ma9 %afts on ea* bank ( ! e/u>y1 & ! fan 9 ! ,monm\?%ire %aft is #dj ft4 9 diamet]1 & #ab ft4 wide4 ,! tunnel gives passage to a l>ge traffic1 num]\s ?r\gh-tra9s betwe5 ! nor? & s\?we/ ( ,engl& mak+ use ( x4 ,,*apt] ,,xviii4 ,,subm>9e ,,tunnel+ 7,cont9u$72 ,,! ,,compress$ ,,air ,,me?od4--,,! ,,milwaukee ,,wat]-,,works ,,tunnel4 ,tunnels excavat$ at %all[ dep? f ! b$ ( ! riv] are liable to cave 9 "u ! great weight ( ! wat] & mat]ial above ! ro(4 ,besides1 ! progress ( ! "w w be greatly int]f]$ ) by ! wat] :i* may rea* ! tunnel pass+ ?r\gh ! loose soil 9 l>ge quantities4 ,to cont5d ) ^! two s\rces ( tr\ble1 diff]5t me?ods ( con/ruct+ subaque\s tunnels h be5 devis$2 !y are3 by compress$ air1 by %ield1 & f9ally by a comb9ation ( ^! two me?ods1 viz41 by %ield & compress$ air4 ,! compress$ air me?od 0 sugge/$ by ,mr4 ,hask91 ! promot] & ! fir/ build] ( ! ,hudson ,riv] tunnel4 ,9 #ahgd1 :5 he began to s9k ! %aft = ! con/ruction ( 8 tunnel1 sev]al subaque\s tunnels _h already be5 driv5 by means ( %ields4 ,mr4 ,hask9 _h ideas ( 8 own1 & ?\ght he c\ld disp5se ) ! %ield & c\ld tru/ to compress$ air1 s9ce he 0 firmly conv9c$ t compress$ air alone c\ld expel ! wat] & tempor>ily support ! ro( ( ! excavation prior to ! build+ ( ! l9+ masonry4 ,9 o!r words1 he expect$ to sub/itute a core ( compress$ air = ! core ( e>? remov$4 ,9 ! pat5t grant$ him = ?is me?od ( tunnel+1 he expresses himself z foll[s3 8,! di/+ui%+ feature ( my sy/em is t1 in/ead ( us+ tempor>y fac+s ( timb] or o!r rigid mat]ial1 ,i rely ^u ! air pressure to resi/ ! cav+ 9 ( ! wall & infiltration ( wat] until ! masonry wall is complet$4 ,! pressure is1 ( c\rse1 to be regulat$ by ! exig5cies ( ! occasion4 ,! effect ( su* a pressure has be5 f\nd to drive wat] 9 f ! surface ( ! excavation1 s t ! s& becomes dry40 ,! compress$ air me?od 0 soon f\nd to be ineffici5t1 ev5 9 ! con/ruction ( ! ,hudson tunnel :]e ! ro( ( ! excavation 0 support$ by timb]+ 9 ! mann] indicat$ 9 ! pilot sy/em4 ,?us l>ge subaque\s railway tunnels _c be driv5 exclusively by ! compress$ air me?od2 /ill x has be5 successfully employ$ 9 ! con/ruction ( small tunnels driv5 = aqu$uct purposes4 ,b ! use ( compress$ air m>k$ a great progress 9 ! art ( subm>9e tunnel+4 ,,! ,,milwaukee ,,wat]-,,works ,,tunnel4 ,! foll[+ description ( ! ,milwaukee ,wat]-,works ,tunnel is an example ( subaque\s tunnels driv5 ?r\gh good soil 9 ! usual mann] employ$ 9 l& tunnels2 b aft]w>d :5 trea*]\s mat]ial 0 enc\nt]$1 ! "w 0 cont9u$ by means ( compress$ air4 ,! new wat] supply intake tunnel = ! city ( ,milwaukee1 ,wis41 is "o ( ! mo/ difficult examples ( tunnel con/ruction :i* ,am]ican eng9e]+ practice has af=d$4 ,! difficulties 7 9 a l>ge measure unexpect$ :5 ! "w 0 decid$ ^u & put "u way4 ,! tunnel began & end$ 9 a h>d1 imp]vi\s clay1 practically a rock1 & all ! prelim9>y inve/igations l$ to ! conclusion t ! same favorable mat]ial w\ld be enc\nt]$ = its entire l5g?4 ,) su* mat]ial a brick-l9$ tunnel #g ft4 9 diamet] pres5t$ no unusual problems2 b aft] ab\t #afdj ft4 _h be5 excavat$ f ! %ore end ! tunnel ran out ( ! h>d clay1 & = ! next #fjj ft4 or m a v>iety ( wat]-be>+ mat]ial 0 enc\nt]$1 :i* tri$ ! skill & pati5ce ( ! eng9e] to _! utmo/4 ,o!r difficulties 7 inde$ met )1 b ^! 7 ( m9or importance 9 comp>ison ) t ( safely & successfully p5etrat+ ! wat]-be>+ drift4 ,! "w ( s9k+ ! %ore %afts & excavat+ ! fir/ #afjj ft4 ( tunnel did n prove especially difficult4 ,a h>d1 compact1 & rock-l clay1 be>+ v little moi/ure1 0 enc\nt]$ all along1 & 0 bla/$ & remov$ 9 ! ord9>y mann]4 ,! only mi%ap :i* occurr$ ) ?is portion ( ! "w 0 ! de/ruction ( ! contractor's boil] plant by fire on ,jan4 #ab1 #ahia1 :i* all[$ ! tunnel to fill ) wat]1 & delay$ "w ab\t a mon?4 ,by ,oct4 #ba1 #ahia1 #afdj ft4 _h be5 driv51 av]ag+ ab\t #f ft4 p] day1 all 9 ! h>d clay4 ,no timb]+ _h be5 necess>y1 & except = ! fir/ #ajj ft4 ( ! tunnel !re 0 v little seepage4 ,on ! aft]noon ( ,oct4 #ba wat] 0 obs]v$ com+ out f "o ( ! drill holes 9 ! head+1 b no att5tion 0 paid to x4 ,%ortly aft] a bla/ 0 fir$1 & 0 imm$iately foll[$ by a ru% ( wat] f ! head+4 ,an unsuccessful attempt 0 made to *eck ! fl[1 & ! pumps 7 />t$2 b !y 7 unable to keep ! wat] d[n1 & aft] sev5 h\rs' h>d "w ! tunnel 0 ab&on$4 ,by ! next morn+ ! tunnel & %aft 7 full ( wat]4 ,sev]al attempts 7 made to empty ! tunnel2 b ! limit$ pump+ capacity 0 n equal to ! task1 & x 0 f9ally decid$ to in/all l>g] pumps4 ,! pump+ _h1 h[ev]1 %[n t ab\t #ajjj gallons ( wat] a m9ute 0 com+ ?r\gh ! leak4 ,) ! increas$ pump+ plant ! tunnel 0 f9ally laid dry ,feb4 #ac1 #ahib4 ,^u exam9ation ! head ( ! drift 0 f\nd to be 9 ! same undi/urb$ condition 9 :i* x 0 left :5 ! wat] broke 9 ?ree mon?s be=e4 ,a brick bulkhead 0 built into ! end ( ! brickwork ( ! tunnel1 & provid$ ) a timb] door = passage1 & two #aj-;94 pipes = ! outlet ( ! wat]4 ,) ^! op5+s clos$1 ! fl[ 0 *eck$ suffici5tly to all[ ! plac+ ( pumps at ! bottom ( ! %ore %aft4 ,mean:ile ! pressure ( ! wat] aga9/ ! bulkhead caus$ dang]\s leakage1 & s aft] ! pumps 7 9 position ! #aj-;94 pipes 7 op5$1 reliev+ ! pressure & all[+ ! wat] its normal rate ( fl[4 ,tr\ble ) ! pumps n[ arose1 & aft] v>i\s /oppages & breaks ! dis*>ge pipe f9ally fell1 disabl+ ! :ole plant4 ,x became necess>y to close ! #aj-;94 pipes 9 ! bulkhead & draw up ! pumps4 ,?is all[$ ! tunnel to aga9 fill ) wat]4 ,aft] ?or\ghly ov]haul+ ! pump+ ma*9]y1 ! contractor aga9 laid ! tunnel dry on ,m>* #ai2 & aft] ! pumps _h be5 p]man5tly plac$ s z to take c>e ( ! wat]1 an exam9ation ( ! "w 0 made4 ,x 0 f\nd t ! wat] 0 com+ f ! nor?1 & ) ! hope ( avoid+ ! difficulties ( ! old head+1 x 0 decid$ to make a dt\r ( ! s\?4 ,on ,april #af "w 0 begun at a po9t ab\t #ij ft4 back f ! face1 & deflect+ ! l9e ab\t #ch t[>d ! s\?4 ,ab\t #ch ft4 f ! angle ( junction a brick bulkhead ) two #h-;94 op5+s 0 built into ! new bore4 ,! "w progress$ successfully = ab\t #ge ft41 :5 wat] 0 aga9 enc\nt]$2 & ^u pu%+ =w>d ! head+1 gravel & s& came 9 su* quantities t x 0 f\nd impracticable to cont9ue ! "w fur!r4 ,on ,june #a ! bulkhead 0 p]man5tly clos$1 & ! "w 9 ?is direction 0 ab&on$4 ,a fur!r & clos] exam9ation 0 n[ made ( ! head+ fir/ ab&on$4 ,^u break+ ?r\gh ! rock-l clay x 0 f\nd t ! wat] came f an und]gr\nd /ream fl[+ f ! nor? ?r\gh a well def9$ *annel 9 r$ clay4 ,?is *annel 0 ab\t #ac ft4 above ! grade ( ! tunnel2 & above x 9 e direction visible 0 a b$ ( h>d1 dry1 r$ clay1 :ile imm$iately 9 front ( ! face ( ! "w 0 a bank ( co>se gravel4 ,fig4 #abb is a sket* ( ! *annel & /ream :]e !y ent]$ ! "w4 ,9 ?is la/ draw+ ! photograph has be5 foll[$ exactly1 no p>ticul> be+ exagg]at$ 9 ! slighte/4 ,! wat] f ?is /ream 0 cle> & pure2 & a *emical analysis %[$ t x 0 n lake wat]1 b mu/ come f "s sep>ate s\rce4 ,illu/ration3 ,,fig4 #abb4--,sket* ,%[+ ,und]gr\nd ,/ream1 ,milwaukee ,wat]-,works ,tunnel4 ,:ile ! eng9e] did n consid] ! difficulty ( proce$+ along ! old l9e insurm\ntable1 x 0 decid$ to be less difficult on ! :ole to g back f #aej ft4 to #age ft4 & deflect ! l9e to ! nor? & upw>d1 s z to pass ov] ! und]gr\nd entrance4 ,in/ead ( all[+ ! wat] to fl[ at its normal rate & take c>e ( x by pump+1 ! contractors desir$ to r$uce ! pump+1 & to ?is end !y con/ruct$ a bulkhead j we/ ( ! deflection t[>d ! s\? ) a view ( %utt+ (f ! wat]4 ,! wat]1 h[ev]1 accumulat$ ) a pressure ( "s #ej lbs4 p] sq4 94 & p5etrat$ ! fill+ ar\nd ! brick l9+ ( ! tunnel1 prev5t+ ! cutt+ ?r\gh ( ! l9+ = ! new l9e4 ,a second bulkhead 0 !n built ab\t #bj ft4 we/ ( ! fir/1 b ) n mu* bett] results1 = ^u clos+ x ! wat] 0 f\nd to leak ?r\gh ! brickwork = a long di/ance we/4 ,f9ally on ,aug4 #b1 #ahib1 ! contractors lift$ _! pumps & all[$ ! tunnel to fill aga9 ) wat]4 ,no fur!r "w 0 done on ! tunnel by ! contractors1 al?\gh !y cont9u$ "w on ! lake %aft = "s mon?s4 ,difficulties _h1 h[ev]1 aris5 "h1 :i* w be describ$ fur!r on2 & f9ally a disagreem5t arose betwe5 ! contractors & ! city ov] ! delay 9 prosecut+ ! tunnel "w & ov] "o or two o!r que/ions1 :i* result$ 9 ! ,city ,c\ncil susp5d+ _! contract & ord]+ ! ,bo>d ( ,public ,works to g ahead ) ! "w4 ,! fir/ /ep to be tak5 by ! eng9e] 0 to pur*ase adequate pump+ ma*9]y & empty ! tunnel4 ,?is 0 effect$ ,jan4 #ag1 #ahid2 & z soon z practicable !reaft] ! two bulkheads 7 remov$ & ! tunnel clean$1 tram-c> tracks laid1 & ev]y?+ prep>$ = "w4 ,x 0 n[ det]m9$ to g ahead on ! orig9al l9e ( ! tunnel if possible1 & ! bulkhead "h 0 remov$ & "w begun4 ,mean:ile1 a safety bulkhead _h be5 built to replace ! fir/ "o torn away4 ,?is 0 provid$ ) a door & dra9age pipes4 ,"w 0 begun on ! orig9al head+1 b _h proce$$ only a little way :5 ! wat] broke 91 driv+ out ! workm54 ,?is 0 remov$ ?ree or f\r times1 :5 ! fl[ sudd5ly increas$ to #cjjj gallons p] m9ute4 ,an exam9ation ( ! lake bottom above ! break %[$ t x _h settl$ d[n1 indicat+ t ! new break connect$ ) ! lake bottom1 & mak+ fur!r "w along ! orig9al l9e out ( ! "q4 ,! "q n[ arose :at x 0 be/ to d4 ,x 0 impracticable to use a %ield1 z ! mat]ial ahead ( ! break requir$ bla/+1 & ! pressure f above 0 enorm\s4 ,on acc\nt ( its exp5se & difficulty ( application ! freez+ process did n seem advisable1 & ! pl5um process 0 likewise out ( ! "q on acc\nt ( ! great pressure :i* w\ld be requir$ at ?is dep?4 ,! dt\r to ! s\? :i* _h be5 made by ! contractor _h be5 unsuccessful1 & _h left ! gr\nd 9 a trea*]\s condition4 ,to depress ! tunnel 0 n advisable1 = x 0 n by any means c]ta9 t ! b$ ( gravel c\ld be avoid$ 9 t way2 &1 moreov]1 x w\ld be necess>y to asc5d aga9 fur!r on1 & ?us leave a trap :i* w\ld effectually cut (f escape to ^? at "w on ! face if wat] aga9 broke into ! tunnel4 ,x 0 f9ally decid$ t ! old plan ( deflect+ ! l9e t[>d ! nor? & upw>d s z to pass ov] ! und]gr\nd /ream %\ld be tri$4 ,a hole 0 !re=e cut ?r\gh ! tunnel l9+ #adcc ft4 f ! %ore1 & "w 0 begun on a dt\r ( #bj t[>d ! nor? & an upw>d grade ( #aj4 ,fair progress 0 made on ?is new l9e1 gradually asc5d+ into solid rock1 until ,may #aj1 :5 ! te/ bor+s1 :i* 7 con/antly made 9 e direction f ! face1 %[$ t s& 0 be+ approa*$4 ,a brick bulkhead 0 !re=e built into ! masonry z a safegu>d1 %\ld x happ5 t wat] 0 enc\nt]$ 9 l>ge quantities4 ,z ! bor+s seem$ to indicate t ! top surface ( ! rock und]ly+ ! s& 0 ne>ly level1 ! l[] half ( ! tunnel 0 fir/ excavat$1 leav+ ab\t #ah ins4 ( ! rock to s]ve z a ro( 7,sket* a1 ,fig4 #abc71 & ! brick inv]t 0 built = a di/ance ( #eb ft4 ,! rock ro( 0 !n c>efully brok5 ?r\gh = %ort di/ances at a "t1 & %ort %eet+ driv5 ahead into ! s&1 :i* prov$ to be a v f9e quicks& fl[+ ?r\gh ! smalle/ op5+s4 ,extreme c>e _h to be tak5 9 ?is "w1 b little by little ! brickwork 0 pu%$ ahead until at a di/ance ( #ij ft4 f ! po9t :]e ! s& 0 fir/ met1 & #bjh ft4 f ! old tunnel1 ! s& /opp$ & ! head+ ent]$ a h>d clay4 ,all ?is "w _h be5 done on an asc5d+ grade1 & ! asc5t 0 cont9u$ ab\t #dj ft4 f>!r 9 ! clay4 ,by ?is "t a suffici5t elevation 0 ga9$ to pass ov] ! und]gr\nd /ream1 & ! tunnel l9e 0 *ang$ to head t[>d ! lake %aft1 & ! grade r$uc$ to a level4 ,! und]gr\nd /ream 0 pass$ )\t tr\ble & ! tunnel cont9u$ = a di/ance ( #ed ft4 )\t difficulty4 ,on ,july #aj ! clay 9 ! head+ sudd5ly s(t5$1 & be=e ! m9]s c\ld secure x by brac+1 ! wat] ru%$ 91 foll[$ by gravel1 fill+ up solidly "s #cd ft4 ( ! tunnel be=e x 0 /opp$ by a timb] bulkhead ha/ily built4 ,illu/ration3 ,longitud9al ,section ,%[+ ,me?od ( ,con/ruction 9 ,rock ,cov]$ ) ,quicks&4 ,sket* 8a04 ,section ,a-,b-,c-,d4 ,sket* 8c04 ,longitud9al ,section ( ,tunnel4 ,sket* 8b04 ,cross ,section ,%[+ ,mann] ( ,con/ruct+ ,l9+ ar\nd ,b\ld]4 ,sket* 8d04 ,,fig4 #abc4--,sket* ,%[+ ,me?ods ( ,l9+1 ,milwaukee ,wat]-,works ,tunnel4 ,^u exam9+ ! lake bottom a cavity ov] #fj ft4 deep & #aj ft4 9 diamet] 0 f\nd directly ov] ! end ( ! tunnel1 :i* _h be5 caus$ by ! gravel break+ into ! tunnel4 ,hav+ n[ rea*$ an elevation :]e x 0 possible to use compress$ air1 x 0 det]m9$ to put 9 d\ble air-locks & use ! pl5um process4 ,! locks 7 built1 & "s #fgj cu4 yds4 ( clay 7 dump$ into ! hole 9 ! lake bottom4 ,on ,aug4 #d ! air-locks 7 tri$ ) #bf lbs4 air pressure2 b1 ^u a tempor>y release ( ! pressure1 ! wat] pass$ ar\nd ! locks & back ( ! tunnel l9+ = "s di/ance1 & ev5 =c$ ?r\gh ! l9+1 c>ry+ consid]able clay & f9e s& ) x4 ,^u s\nd+ ! lake bottom x 0 f\nd t ! cavity _h aga9 increas$ to a dep? ( #fe ft41 :]eupon an additional #fjj cu4 yds4 ( clay 7 dump$ into x4 ,on acc\nt ( ! wat] leak+ ?r\gh ! brickwork1 ! only dry place to cut ?r\gh ! brickwork & build 9 an air-lock 0 j ahead ( ! brick bulkhead4 ,?is lock 0 complet$ ,aug4 #bg1 & to avoid enc\nt]+ ! dang] ( ! direct connection ) ! lake at ! end ( ! drift1 x 0 decid$ to make ano!r dt\r to ! nor?4 ,on ,aug4 #bh1 !re=e1 ! brick on ! nor? side ( ! tunnel #ab ft4 back f ! end ( ! brickwork 0 cut ?r\gh "u #be lbs4 air pressure1 & "w proce$$ 9 good1 h>d clay4 ,! orig9al air-lock 0 cut out & a new lock built into ?is clay ab\t #cd ft4 f ! la/ dt\r1 to be us$ 9 case ( fur!r difficulties4 ,aft] build+ ! tunnel = ab\t #hj ft4 f ! dt\r1 ! s\nd+s aga9 indicat$ ! approa* to gravel & wat]1 & on ,oct4 #ad ! wat] broke ?r\gh f ! bottom 9 su* volume & ) su* =ce t ! m5 ran out1 clos+ e air-lock & ! valves ( e dra9 9 _! ha/e to escape1 until ! brick bulkhead 0 rea*$4 ,x 0 ) great difficulty t ! portion ( ! tunnel up to ! la/ air-lock 0 recov]$ & clean$ out4 ,x 0 n[ recogniz$ t a pressure ( f #ch to #dj lbs4 ( air w\ld be ne$$ to hold ?is wat]1 & accord+ly ano!r compressor 0 add$ to ! plant4 ,) a pressure ( #cf lbs4 ! wat] 0 driv5 out & ! "w aga9 />t$4 ,at ?is "t also an additional #cej cu4 yds4 ( clay 7 dump$ into ! hole 9 ! lake bottom4 ,altoge!r1 #afbj cu4 yds4 ( clay _h be5 put into ?is hole4 ,loose gravel & b\ld]s1 "s ( imm5se size1 7 n[ enc\nt]$1 & ! "w became exce$+ly difficult on acc\nt ( ! great escape ( air4 ,! int]/ices betwe5 ! gravel & b\ld]s 7 n fill$ ) silt or s&1 b conta9$ wat]4 ,moreov]1 ?is mat]ial ext5d$ upw>d to ! lake bottom1 z 0 %[n by ! escape ( air at ! surface ( ! lake4 ,= an area ( sev]al hundr$ squ>e feet ! surface ( ! wat] resembl$ a pot ( boil+ wat]4 ,at times ! air w\ld escape v rapidly2 & aga9 only a few bubbles w\ld %[4 ,x ne$ h>dly be said t ! "w 9 ?is gravel 0 v sl[4 ,x 0 impossible to bla/ or to te> out ! l>ge b\ld]s :ole1 z s mu* surface w\ld be expos$ t an inru% ( wat] w\ld take place despite ! air pressure4 ,! me?od ( proc$ure 0 to excavate a head+ & build ! brick ro( ar* fir/1 & !n to take out ! b5* & build ! inv]t4 ,fig4 #abc gives a numb] ( sket*es %[+ h[ ! "w 0 done4 ,a %ort piece ( head+ 0 tak5 out1 ! top & face ( ! b5* be+ mean:ile pla/]$ ) clay 7,sket*es b & c1 ,fig4 #abc7 to r$uce ! escape ( air1 & !n ! ro( ar* 0 built & support$ on side sills re/+ on ! b5*4 ,bit by bit ! ro( ar* 0 pu%$ =w>d until "s little di/ance _h be5 complet$1 !n ! head+ 0 pla/]$ ) clay & ! b5* tak5 out little by little & ! inv]t built4 ,all ! gravel except ! small area ^u :i* "w 0 actually 9 progress 0 kept ?or\ghly pla/]$ ) clay2 & z ! air escap$ ?r\gh ! complet$ brickwork v rapidly1 wat] 0 all[$ to cov] a portion ( ! inv]t 7see ,sket* c1 ,fig4 #abc71 s z to r$uce ! area ( escape4 ,:5 a l>ge b\ld] 0 rea*$1 :i* lay p>tly )9 & p>tly )\t ! tunnel section1 ! l9+ 0 built out & ar\nd x1 z %[n 9 ,sket* d1 ,fig4 #abc4 ,! b\ld] 0 !n brok5 & tak5 out4 ,all ?r\gh ?is gravel b$ ! cross-section ( ! l9+ is made irregul> by ! con/ruction ( ^! pockets 9 ! l9+ to get ar\nd b\ld]s4 ,sometimes !y 7 on "o side & sometimes on ! o!r1 or on bo?1 or at ! top or bottom4 ,9 fact1 !re 0 no regul>ity4 ,despite ! haz>d & dang] ( ?is "w1 cont9ual progress 0 made1 ?\gh sometimes x 0 only #d ft4 ( complet$ tunnel p] week1 work+ night & day2 &1 if "s cases ( caisson disease be except$1 ! only mi%ap occurr+ 0 a fire :i* got into ! timb] pack+ beh9d ! l9+ & caus$ "s tr\ble4 ,f ! gravel ! tunnel ran into clay & quicks&1 & !n into h>d1 dry clay simil> to t enc\nt]$ ne> ! %ore4 ,"s difficulty 0 _h ) ! quicks&1 b x 0 successfully ov]come2 & :5 ! h>d clay 0 /ruck1 ! tr\ble1 z f> z ! "w f ! %ore %aft 0 conc]n$1 0 virtually ov]4 ,mean:ile1 a diff]5t set ( afflictions _h come ^u ! eng9e] & contractors 9 s9k+ ! lake %aft & driv+ ! head+ t[>d %ore4 ,?is %aft 0 int5d$ to be built by s9k+ a ca/-iron cyl9d] #aj ft4 9 diamet]1 made up ( sections bolt$ toge!r4 ,"w 0 begun ,july #e1 #ahib1 & ! s9k+ 0 accompli%$ fir/ by weight+ ! cyl9d]1 & aft]w>ds by pump+ out ! s& & wat] )9 x until ! pressure f ! outside broke ?r\gh "u ! cutt+ edge & =c$ ! s& into ! cyl9d]1 all[+ x to s9k a little4 ,f #aj to #cj cu4 yds4 ( s& 7 c>ri$ into ! cyl9d] ea* "t1 & f9ally x 0 fe>$ t if ! process cont9u$1 ! crib1 :i* _h be5 previ\sly erect$1 w\ld be und]m9$4 ,on ,sept4 #f1 !re=e1 ! contractors 7 ord]$ to discont9ue ?is me?od ( "w4 ,no *ange 0 made1 h[ev]1 until ,oct4 #a1 :5 ! cyl9d] _h rea*$ a dep? ( #fh ft41 & by ?is "t !re 0 q a l>ge cavity und]nea? ! crib4 ,?is 0 refill$1 & ! cyl9d] pump$ out1 & excavation begun inside ( x4 ,on ,oct4 #aa a #b-;ft4 deep r+ ( brickwork 0 laid und]nea? ! cutt+ edge2 b 9 try+ to put 9 ano!r r+ b5ea? ! fir/1 two days lat]1 ! s& & wat] broke ?r\gh ! bottom1 driv+ ! m5 out1 & fill+ ! cyl9d] to a dep? ( #af ft4 ) s&4 ,! pumps 7 />t$1 b ! wat] c\ld n be l[]$ to a great] dep? ?an #fj ft4 ,at ! reque/ ( ! contractors1 ! city eng9e] _h a bor+ made at ! c5t] ( ! %aft to det]m9e ! "* ( ! mat]ial to be fur!r p5etrat$4 ,?is bor+ %[$ t s& mix$ ) loam & gravel w\ld be f\nd = a dep? ( #bf ft41 !n w\ld come #ae ft4 ( r$ clay1 & f9ally a lay] ( h>d clay l t p5etrat$ by ! %ore end ( ! tunnel4 ,ab\t ! middle ( ,decemb] ! contractors made ano!r attempt to pump ! %aft1 b f9d+ t ! wat] came 9 at ! rate ( #be gallons a m9ute1 ab&on$ ! attempt4 ,9 ! latt] "p ( ,febru>y prep>ations 7 made to put an air-lock 9 ! %aft & use compress$ air4 ,h>dly _h ! "w be5 begun by ?is sy/em :51 on ,april #bj1 #ahic1 a t]rific ea/]ly /orm swept ! top ( ! crib b>e ( ! build+s & ma*9]y1 & dr[n$ all b "o ( ! #ae m5 at "w !re4 ,?is disa/] delay$ ! "w = "s "t1 b 9 ,june ! contractors erect$ a new build+ & new ma*9]y1 & resum$ "w4 ,v little progress 0 made2 & ! air escap$ s rapidly t x loos5$ ! s& surr\nd+ ! %aft & r$uc$ ! friction to su* an ext5t t on ,july #bh ! entire cyl9d] lift$ bodily ab\t #f ft41 & s& ru%$ 91 fill+ ! l[] "p ( ! cyl9d] to )9 #de ft4 ( ! lake surface4 ,no fur!r "w 0 done by ! contractors al?\gh !y submitt$ a proposition to s9k a /eel cyl9d] inside ! ca/-iron cyl9d] & ext5d+ f #e ft4 above datum to #ajj ft4 bel[ datum = #cjj p] ft4 ,?is proposition 0 refus$ by ! city2 & s9ce "w on ! tunnel prop] _h be5 ab&on$ by ! contractors "s "t be=e1 z _h already be5 describ$1 ! city susp5d$ _! contract on ,oct4 #ai4 ,on ,oct4 #cj a contract 0 made ) ,mr4 ,?os4 ,murphy ( ,milwaukee1 ,wis41 to s9k a /eel cyl9d] inside ! old iron cyl9d]4 ,! wat] 0 fir/ pump$ out ( ! old cyl9d]1 & a timb] bulkhead built at ! bottom4 ,on ?is ! /eel cyl9d] 0 built1 & !n ! bulkhead 0 remov$4 ,air pressure 0 put on1 & ! excavation proce$$ successfully until ! bottom lay] ( clay 0 met )1 :5 all *ances = tr\ble ceas$4 ,! cyl9d]1 z x 0 complet$1 p5etrat$ #i ft4 into ! h>d clay1 & 0 und]p9n$ ) brickwork = a dep? ( #bi ft4 or m1 to a po9t #d ft4 bel[ ! grade l9e ( ! tunnel4 ,at ! l[] end1 ! section ( ! %aft 0 *ang$ f a circle to a squ>e4 ,lat] ! /eel cyl9d] 0 l9$ ) brick4 ,on ,m>* #bh1 #ahid1 an agreem5t 0 made ) ,mr4 ,?os4 ,murphy to con/ruct ! tunnel f ! lake %aft t[>d ! %ore4 ,except t consid]able wat] 0 enc\nt]$1 :i*1 ow+ to inadequate pump+ ma*9]y1 fill$ ! tunnel & %aft at two diff]5t times1 & _h to be remov$1 no v great difficulty 0 _h ) ?is "p ( ! "w4 ,on ,july #bh1 #ahie1 ! head+s f ! lake & %ore %afts met4 ,mean:ile ! ca/-iron pipe intake1 ! intake crib1 etc41 _h be5 complet$1 & practically all t rema9$ to be done 0 to clean ! tunnel & lift ! pump+ ma*9]y at ! %ore %aft4 ,dur+ ! clean+1 ! air pressure _h be5 kept up on acc\nt ( ! leakage ?r\gh ! brick l9+1 &1 inde$1 ! pressure 0 kept up until ! la/ possible mom5t1 & ev]y?+ made ready = remov+ ! air-locks1 bulkheads1 pumps1 etc41 9 ! lea/ possible "t4 ,! pumps 7 ! la/ to come out4 ,,*apt] ,,xix4 ,,subm>9e ,,tunnel+ 7,cont9u$74 ,,! ,,%ield ,,sy/em4 ,hi/orical ,introduction4--,! inv5tion ( ! %ield sy/em ( tunnel+ ?r\gh s(t gr\nd is g5]ally accr$it$ to ,sir ,isamb>d ,brunel1 a ,fr5*man born 9 #agfi1 :o emigrat$ to ! ,unit$ ,/ates 9 #agic1 :]e he rema9$ six ye>s1 & !n w5t to ,engl&1 9 :i* c\ntry 8 epo*-mak+ inv5tion 9 tunnel+ 0 develop$ & successfully employ$ 9 build+ ! fir/ ,?ames tunnel1 & :]e he di$ 9 #ahdi1 a few ye>s aft] ! completion ( ?is great "w4 ,sir ,isamb>d is said to h obta9$ ! idea ( employ+ a %ield to tunnel s(t gr\nd f obs]v+ ! "w ( %ip-worms4 ,he notic$ t ?is little animal _h a head provid$ ) a bor+ app>atus ) :i* x dug its way into ! wood1 & t its body ?rew (f a secretion :i* l9$ ! hole beh9d x & r5d]$ x imp]vi\s to wat]4 ,to duplicate ?is op]ation by me*anical means on a l>ge en\gh scale to make x applicable to ! con/ruction ( tunnels 0 ! plan :i* occurr$ to ! eng9e]2 & h[ closely he foll[$ 8 animate model may be se5 by exam9+ ! draw+s ( 8 fir/ %ield1 = :i* he secur$ a pat5t 9 #ahah4 ,briefly describ$1 ?is device consi/$ ( an iron cyl9d] hav+ at its front end an aug]-l cutt]1 ^: revolution 0 int5d$ to %ove away ! mat]ial ahead & ?us advance ! cyl9d]4 ,z ! cyl9d] advanc$ ! p]imet] ( ! hole beh9d 0 to be l9$ ) a spiral %eet-iron plat+1 :i* 0 to be /r5g!n$ ) an int]ior l9+ ( masonry4 ,x w be se5 t ! me*anical resemblance ( ?is device to ! %ip-worm1 on :i* x is alleg$ to h be5 model$1 0 rem>kably close4 ,9 ! same pat5t 9 :i* ,sir ,isamb>d secur$ protection = 8 me*anical %ip-worm he claim$ equal rights ( inv5tion = ano!r %ield1 :i* is ( f> great] importance 9 be+ ! prototype ( ! %ield actually employ$ by him 9 con/ruct+ ! fir/ ,?ames tunnel4 ,?is alt]native inv5tion1 if x may be s t]m$1 consi/$ ( a gr\p ( sep>ate cells :i* c\ld be advanc$ "o or m at a "t or all toge!r4 ,! sides ( ^! cells 7 to be provid$ ) friction roll]s to enable !m to slide easily ^u ea* o!r2 & x 0 also specifi$ t ! pref]able motive p[] = advanc+ ! cells 0 hydraulic jacks4 ,to summ>ize briefly1 !re=e1 ! two inv5tions ( ,brunel compreh5d$ ! protect+ cyl9d] or %ield1 ! closure ( ! face ( ! excavation1 ! cellul> division1 ! hydraulic-jack propell+ p[]1 & cyl9drical iron l9+1 :i* are ! ess5tial *>act]i/ics ( ! mod]n %ield sy/em ( tunnel+4 ,! next /ep requir$ 0 ! actual pro( ( ! practicability ( ,brunel's inv5tions1 & ?is soon came4 ,^? :o h read ! hi/ory ( ! fir/ ,?ames tunnel w recall ! e>ly unsuccessful attempts at con/ruction :i* _h disc\rag$ ,engli% eng9e]s4 ,five ye>s aft] ,brunel's pat5t 0 secur$ a company 0 =m$ to und]take ! task aga91 ! plan be+ to use ! %ield sy/em1 "u ! p]sonal direction ( its inv5tor z *ief eng9e]4 ,= ?is "w ,brunel select$ ! cellul> %ield m5tion$ z an alt]native con/ruction 9 8 orig9al pat5t4 ,he also *ose to make ?is %ield rectangul> 9 =m4 ,?is *oice is commonly acc\nt$ = by ! fact t ! /rata to be p5etrat$ by ! tunnel 7 practically horizontal1 & t x 0 assum$ by ! eng9e] t a rectangul> %ield w\ld = "s reason be/ resi/ ! pressures :i* w\ld be develop$4 ,:atev] ! reason may h be5 = ! *oice1 ! fact rema9s t a rectangul> %ield 0 adopt$4 ,! tunnel z design$ consi/$ ( two p>allel horse%oe tunnels1 #ac ft4 #i ins4 wide & #af ft4 #d ins4 high & #abjj ft4 long1 sep>at$ f ea* o!r by a wall #d ft4 ?ick1 pi]c$ by #fd ar*$ op5+s ( #d ft4 span1 ! :ole be+ surr\nd$ ) massive brickwork built to a rectangul> section measur+ ov] all #ch ft4 wide & #bb ft4 high4 ,! fir/ %ield design$ by ,brunel = ! "w prov$ inadequate to resi/ ! pressures1 & x 0 replac$ by ano!r some:at l>g] %ield ( sub/antially ! same design1 b ( improv$ con/ruction4 ,?is la/ %ield 0 #bb ft4 #c ins4 high & #cg ft4 #f ins4 wide4 ,x 0 divid$ v]tically into twelve sep>ate ca/-iron frames plac$ close side by side1 & ea* frame 0 divid$ horizontally into ?ree cells capable ( sep>ate movem5t1 b connect$ by a peculi> articulat$ con/ruction1 :i* is indicat$ 9 a g5]al way by ,fig4 #abd4 ,to close or cov] ! face ( ! excavation1 pol+-bo>ds held 9 place by num]\s small screw-jacks 7 employ$4 ,ea* cell or ea* frame c\ld be advanc$ indep5d5tly ( ! o!rs1 ! p[] = ?is op]ation be+ obta9$ by means ( screw-jacks abutt+ aga9/ ! complet$ masonry l9+4 ,briefly describ$1 ! mode ( proc$ure 0 to remove ! pol+-bo>ds 9 front ( ! top cell ( "o frame1 & excavate ! mat]ial ahead = ab\t #f ins4 ,?is be+ done1 ! top cell 0 advanc$ #f ins4 by means ( ! screw-jacks1 & ! pol+-bo>ds 7 replac$4 ,! middle cell ( ! frame 0 !n advanc$ #f ins4 by repeat+ ! same process1 & f9ally ! op]ation 0 duplicat$ = ! bottom cell4 ,) ! advance ( ! bottom cell "o frame _h be5 pu%$ ahead #f ins41 & by a succession ( su* op]ations ! o!r elev5 frames 7 advanc$ a di/ance ( #f ins41 "o aft] ! o!r1 until ! :ole %ield occupi$ a position #f ins4 9 advance ( t at :i* "w 0 begun4 ,! next /ep 0 to fill ! #f-;94 space beh9d ! %ield ) a r+ ( brickwork4 ,illu/ration3 ,,fig4 #abd4--,longitud9al ,section ( ,brunel's ,%ield1 ,fir/ ,?ames ,tunnel4 ,! illu/ration1 ,fig4 #abd1 is ! section p>allel to ! v]tical plane ( ! tunnel ?r\gh ! c5t] ( "o ( ! frames1 & x %[s q cle>ly ! complicat$ details ( ! %ield con/ruction4 ,two features :i* are to be p>ticul>ly not$ are ! susp5d$ /ag+ & c5t]+ = con/ruct+ ! ro( ar*1 & ! top plate ( ! %ield ext5d+ back & ov]lapp+ ! ro( masonry s z to close completely ! ro( ( ! excavation & prev5t its fall+4 ,not)/&+ its complicat$ con/ruction & unwieldy weight ( #abj tons1 ?is %ield work$ successfully1 & dur+ sev]al mon?s ! con/ruction proce$$ at ! rate ( #b ft4 e #bd h\rs4 ,!re 7 two irruptions ( wat] & mud f ! riv] dur+ ! "w1 b ! ap]tures 7 effectually /opp$ by heav+ bags ( clay into ! holes 9 ! riv] b$1 & cov]+ !m ov] ) t>paul91 ) a lay] ( gravel ov] all4 ,! tunnel 0 complet$ 9 #ahdc1 at a co/ ( ab\t #efjj p] l9eal y>d1 & #bj ye>s f ! "t "w 0 fir/ comm5c$1 includ+ all delays4 ,illu/ration3 ,,fig4 #abe4--;,fir/ ,%ield ,inv5t$ by ,b>l[4 ,! next tunnel to be built by ! %ield sy/em 0 ! tunnel "u ,london ,t[] con/ruct$ by ,b>l[ & ,grea!ad & begun 9 #ahfi4 ,9 #ahfc ,mr4 ,pet] ,w4 ,b>l[ secur$ a pat5t 9 ,engl& = a sy/em ( tunnel con/ruction compris+ ! use ( a circul> %ield & a cyl9drical ca/-iron l9+4 ,! %ield1 z %[n by ,fig4 #abe1 0 simply an iron or /eel plate cyl9d]4 ,! cyl9d] plates 7 ?9n$ d[n 9 front to =m a cutt+ edge1 & !y ext5d$ f> en\gh back at ! re> to enable ! advance r+ ( ! ca/-iron l9+ to be set up )9 ! cyl9d]4 ,9 simplicity ( =m ?is %ield 0 mu* sup]ior to ,brunel's2 b x seems v d\btful1 s9ce x _h no diametrical brac+ ( any sort1 :e!r x w\ld ev] h )/ood ! comb9$ pressure ( ! screw-jacks & ( ! surr\nd+ e>? 9 actual op]ation )\t s]i\s di/ortion1 &1 probably1 total collapse4 ,x %\ld also be not$ t ,b>l['s %ield made no provision = protect+ ! face ( ! excavation1 al?\gh ! inv5tor did /ate t if ! soil made x necess>y su* a protection c\ld be us$4 ,! pat5t provid$ = ! injection ( liquid cem5t beh9d ! ca/-iron l9+ to fill ! annul> space left by ! advanc+ tail-plates ( ! %ield4 ,al?\gh ,b>l[ made vigor\s ef=ts to get 8 %ield us$1 x 0 n until #ahfh t an opportunity pres5t$ itself4 ,9 ! meantime ! inv5tor _h be5 /udy+ h[ to improve 8 orig9al device1 & 9 #ahfh he secur$ additional pat5ts cov]+ ^! improvem5ts4 ,briefly describ$1 !y consi/$ 9 p>tly clos+ ! %ield ) a diaphragm z %[n by ,fig4 #abf4 ,! un9clos$ portion ( ! %ield is "h %[n at ! c5t]1 b ! pat5t specifi$ t x might also be locat$ bel[ ! c5t] 9 ! bottom "p ( ! %ield4 ,! idea ( ! con/ruction 0 t 9 case ( an irruption ( wat] ! upp] portion ( ! %ield c\ld be kept op5 by air pressure1 & "w prosecut$ 9 ?is op5 space until ! %ield _h be5 driv5 ahead suffici5tly to close ! ap]ture1 :5 ! normal condition ( affairs w\ld be resum$4 ,?is 0 obvi\sly an improvem5t ( real m]it4 ,! p>tial diaphragm also s]v$ to /iff5 ! %ield some:at aga9/ collapse1 b ! ?9 plate cutt+-edges & mo/ ( ! o!r /ructural weaknesses 7 left unalt]$4 ,to summ>ize briefly ! improvem5ts due to ,b>l['s "w1 we h3 ! con/ruction ( ! %ield 9 a s+le piece2 ! use ( compress$ air & a p>tial diaphragm = keep+ ! upp] "p ( ! %ield op5 9 case ( irruptions ( wat]2 & ! injection ( liquid cem5t to fill ! voids beh9d ! l9+4 ,illu/ration3 ,longitud9al ,section4 ,cross ,section4 ,,fig4 #abf4--,second ,%ield ,inv5t$ by ,b>l[4 ,turn+ n[ to ! ,london ,t[] tunnel "w1 x may fir/ be not$ t ,b>l[ f\nd "s difficulty 9 f9d+ a contractor :o 0 will+ to und]take ! job1 s little confid5ce _h eng9e]s g5]ally 9 8 %ield sy/em4 ,"o man1 h[ev]1 ,mr4 ,j4 ,h4 ,grea!ad1 p]ceiv$ t ,b>l['s device pres5t$ m]it1 al?\gh its design & con/ruction 7 defective1 & he f9ally und]took ! "w & c>ri$ x to a brilliant success4 ,! tunnel 0 #acej ft4 long & #g ft4 9 diamet]1 & p5etrat$ compact clay4 ,"w 0 begun on ! fir/ %ore %aft on ,feb4 #ab1 #ahfi1 & ! tunnel 0 complet$ ! foll[+ ,*ri/mas1 or 9 some?+ %ort ( elev5 mon?s1 at a co/ ( #ad1ejj4 ,! %ield us$ 0 ,b>l['s idea put into practical %ape by ,grea!ad4 ,x consi/$ ( an iron cyl9d]1 or1 m prop]ly1 a fru/um ( a cone ^: circumf]5tial sides 7 v slightly incl9$ to ! axis1 ! idea be+ t ! friction w\ld be less if ! front end ( ! %ield 7 slightly l>g] ?an ! re> end4 ,! %ell ( ! cone 0 made ( -94 plates4 ,! ?9n$ plate cutt+-edge ( ,b>l['s %ield 0 replac$ by ,grea!ad ) a circul> r+ ( ca/ iron4 ,grea!ad also alt]$ ! con/ruction ( ! diaphragm by arrang+ ! angle /iff5]s s t !y ran horizontally & v]tically1 & by fa/5+ ! diaphragm plates to an int]ior ca/-iron r+ connect$ to ! %ell plates4 ,?is 0 a decid$ /ructural improvem5t1 b x 0 accompani$ ) ano!r modification :i* 0 q z decid$ a retrogression f ,b>l['s design4 ,grea!ad made ! diaphragm op5+ rectangul> & to ext5d v ne>ly f ! top to ! bottom ( ! %ield1 ?us ab&on+ ! elem5t ( safety provid$ by ,b>l[ 9 case ( an irruption ( wat]4 ,=tunately ! mat]ial p5etrat$ by ! %ield = ! ,t[] tunnel 0 s compact t no tr\ble 0 _h f wat]2 b ! dang]\s "* ( ! con/ruction 0 "s ye>s aft]w>ds disa/r\sly prov5 9 driv+ ! ,y>ra ,riv] tunnel at ,melb\rne1 ,au/ralia4 ,to drive 8 %ield ,grea!ad employ$ six #b-;94 screw-jacks capable ( develop+ a total =ce ( #fj tons4 ,! tails ( ! jack bore aga9/ ! complet$ l9+1 :i* consi/$ ( ca/-iron r+s #ah ins4 wide & 94 ?ick1 ea* r+ be+ made up ( a cr[n piece & ?ree segm5ts4 ,! diff]5t segm5ts & r+s 7 provid$ ) d\ble 7ext]ior & int]ior7 flanges1 by means ( :i* !y 7 bolt$ toge!r4 ,! soil beh9d ! l9+ 0 fill$ ) liquid cem5t inject$ ?r\gh small holes by means ( a h& pump4 ,illu/ration3 ,,fig4 #abg4--,%ield ,sugge/$ by ,grea!ad = ! ,propos$ ,nor? & ,s\? ,woolwi* ,subway4 ,illu/ration3 ,,fig4 #abh4--;,bea*'s ,%ield ,us$ on ,broadway ,pneumatic ,railway ,tunnel4 ,! rem>kable success ( ! ,london ,t[] tunnel enc\rag$ ,b>l[ to =m 9 #ahga a company to tunnel ! ,?ames betwe5 ,s\?w>k & ! ,city1 & ,grea!ad1 9 #ahgf1 to project a tunnel "u ! same wat]way kn[n z ! ,nor? & ,s\? ,woolwi* ,subway4 ,b>l['s concession 0 abrogat$ by ,p>liam5t 9 #ahgc1 )\t any "w hav+ be5 done4 ,grea!ad progress$ f> en\gh ) 8 ent]prise to con/ruct a %ield & a l>ge am\nt ( ! iron l9+ :5 ! contractors ab&on$ ! "w4 ,f ! brief description ( 8 %ield giv5 by ,grea!ad to ! ,london ,society ( ,civil ,eng9e]s1 x conta9$ sev]al important diff]5ces f ! %ield built by him = ! ,london ,t[] tunnel1 z is %[n by ,fig4 #abg4 ,! *anges :i* des]ve p>ticul> notice are ! great ext5sion ( ! %ield beh9d ! diaphragm1 ! curv$ =m ( ! diaphragm1 & ! use ( hydraulic jacks4 ,grea!ad _h also design$ = ?is "w a special crane to be us$ 9 erect+ ! ca/-iron segm5ts ( ! l9+4 ,illu/ration3 ,,fig4 #abi4--,%ield = ,city & ,s\? ,london ,railway4 ,:ile ^! works _h be5 progress+ 9 ,engl&1 ,mr4 ,bea*1 an ,am]ican1 receiv$ a pat5t 9 ! ,unit$ ,/ates = a tunnel %ield ( ! con/ruction %[n by ,fig4 #abh1 :i* 0 fir/ tri$ practically 9 con/ruct+ a %ort l5g? ( tunnel "u ,broadway = ! ne>ly =gott5 ,broadway ,pneumatic ,und]gr\nd ,railway4 ,?is %ield1 z is indicat$ by ! illu/ration1 consi/$ ( a cyl9d] ( wood ) an iron-cutt+-edge & an iron tail-r+4 ,ext5d+ transv]sely across ! %ield at ! front end 7 a numb] ( horizontal iron plates or %elves ) cutt+-edges1 z %[n cle>ly by ! draw+4 ,! %ield 0 mov$ ahead by means ( a numb] ( hydraulic jacks suppli$ ) p[] by a h& pump atta*$ to ! %ield4 ,by means ( suitable valves all or any less] numb] ( ^! jacks c\ld be op]at$1 & by ?us regulat+ ! action ( ! motive p[] ! direction ( ! %ield c\ld be alt]$ at w4 ,"w 0 ab&on$ on ! ,broadway tunnel 9 #ahgj4 ,9 #ahga-b ,bea*'s %ield 0 us$ 9 build+ a %ort circul> tunnel #h ft4 9 diamet] 9 ,c9c9nati1 & a little lat] x 0 introduc$ into ! ,clevel& wat]-works tunnel #h ft4 9 diamet]4 ,9 ?is latt] "w1 :i* 0 ?r\gh a v trea*]\s soil1 ! %ield gave a great deal ( tr\ble1 & 0 f9ally s flatt5$ by ! pressures t x 0 ab&on$4 ,! obvi\sly defective features ( ?is %ield 7 its want ( v]tical brac+ & ! lack ( any means ( clos+ ! front 9 s(t soil4 ,illu/ration3 ,,fig4 #acj4--,%ield = ,/4 ,clair ,riv] ,tunnel4 ,illu/ration3 ,longitud9al ,section4 ,cross ,section4 ,,fig4 #aca4--,%ield = ,blackwall ,tunnel4 ,) ! =ego+ brief review ( ! e>ly developm5t ( ! %ield sy/em ( tunnel+1 we h arriv$ at a po9t :]e ! me?ods ( mod]n practice c be /udi$ intellig5tly4 ,9 ! pages :i* foll[ we %all fir/ illu/rate fully ! con/ruction ( a numb] ( %ields ( typical & special con/ruction1 & foll[ ^! illu/rations ) a g5]al discussion ( pres5t practice 9 ! v>i\s details ( %ield con/ruction4 ,illu/ration3 ,transv]se ,section4 ,longitud9al ,section4 ,,fig4 #acb4--;,elliptical ,%ield = ,cli*y ,sew] ,tunnel1 ,p>is4 ,illu/ration3 ,longitud9al ,section4 ,cross ,section4 ,,fig4 #acc4--,semi-elliptical ,%ield = ,cli*y ,sew] ,tunnel4 ,mr4 ,raynald ,lg\ez1 9 8 excell5t book ^u ! %ield sy/em ( tunnel+1 consid]s t tunnel %ields may be divid$ into ?ree classes /ructurally1 accord+ to ! "* ( ! mat]ial :i* !y are design$ to p5etrate4 ,9 ! fir/ class he places %ields design$ to "w 9 a /iff & comp>atively /able soil1 l ! well-kn[n ,london clay2 9 ! second class are plac$ ^? con/ruct$ to "w 9 s(t clays & silts2 & 9 ! ?ird class ^? int5d$ = soils ( an un/able granul> nature4 ,?is classification w1 9 a g5]al way1 be kept by ! writ]4 ,z a repres5tative %ield ( ! fir/ class1 ! "o design$ = ! ,city & ,s\? ,london ,railway is illu/rat$ 9 ,fig4 #abi4 ,! %ields = ! ,london ,t[] tunnel1 ! ,wat]loo & ,city ,railway1 ! ,glasg[ ,di/rict ,subway1 ! ,siphons ( ,cli*y & ,concorde 9 ,p>is1 & ! ,glasg[ ,port tunnel1 are ( ! same g5]al design & con/ruction4 ,to repres5t %ields ( ! second class1 ! ,/4 ,clair ,riv] & ,blackwall %ields are %[n 9 ,figs4 #acj & #aca4 ,! %ields = ! ,m]sey ,riv]1 ! ,hudson ,riv]1 & ! ,ea/ ,riv] tunnels also belong to ?is class4 ,to repres5t %ields ( ! ?ird class1 ! elliptical & semi-elliptical %ields ( ! ,cli*y tunnel "w 9 ,p>is are %[n by ,figs4 #acb & #acc4 ,! semi-circul> %ield ( ! ,bo/on ,subway is illu/rat$ by ,fig4 #acd4 ,illu/ration3 ,half ,transv]se ,section ,a-,b4 ,half ,re>-,end ,elevation4 ,details ( ,ca/+ ,support+ ,ends ( ,jacks4 ,details ( ,ca/+s "u ,ends ( ,gird]s4 ,longitud9al ,section ,c-,d4 ,,fig4 #acd4--,ro( ,%ield = ,bo/on ,subway4 ,prel9i's ,%ield4--,9 clos+ ?is %ort review m5tion w be made ( a new %ield design$ & pat5t$ by ! ,au?or & %[n 9 ,fig4 #ace4 ,x is an articulat$ %ield compos$ ( two sep>at$ %ields ^: out] %ells ov]lap ea* o!r4 ,! %ields are connect$ toge!r by means ( hydraulic jacks atta*$ all ar\nd ! two diaphragms4 ,betwe5 ^! diaphragms is a l>ge inclos$ space call$ a safety *amb]1 :]e ! m5 c )draw 9 case ( accid5ts & :]e ! air c be imm$iately rais$ to ! requir$ pressure4 ,?is is an advantage 9 case ( bl[-outs1 because ! flood+ ( ! tunnel is prev5t$1 :ile ! accid5t is limit$ to only a few feet f ! front4 ,on acc\nt ( ! %ield be+ advanc$ half at a "t x is always "u control & is ?us bett] direct$ ?r\gh grade & alignm5t4 ,besides1 ?is %ield w n rotate ar\nd its axis & consequ5tly x c be built ( any %ape1 ?us p]mitt+ ! con/ruction ( subaque\s tunnels ( any cross-section & ev5 ) a wid] f\ndation1 :i* is impossible to-day ) ! ord9>y rotat+ %ields ( circul> cross-section4 ,illu/ration3 ,,fig4 #ace4--,transv]sal & ,longitud9al ,section ( ,prel9i's ,%ield4 ,,%ield ,,con/ruction4 ,g5]al ,=m4--,tunnel %ields are usually cyl9drical or semi-cyl9drical 9 cross-section4 ,! cyl9d] may be circul>1 elliptical1 or oval 9 section4 ,f> ! great] numb] ( %ields us$ 9 ! pa/ h be5 circul> cyl9d]s2 b 9 "o "p ( ! sew] tunnel ( ,cli*y1 9 ,p>is1 an elliptical %ield ) its major axis horizontal1 0 us$1 & ! ,g]man eng9e]1 ,h]r ,mack5s51 has design$ an oval %ield1 ) its major axis v]tical4 ,a semi-elliptical %ield 0 employ$ on ! ,cli*y tunnel1 & semi-circul> %ields 7 us$ on ! ,baltimore ,belt ,l9e tunnel & ! ,bo/on ,subway 9 ,am]ica4 ,g5]ally1 also1 tunnel %ields are "r cyl9d]s2 t is1 ! front & re> edges are 9 v]tical planes p]p5dicul> to ! axis ( ! cyl9d]4 ,occasionally1 h[ev]1 !y are oblique cyl9d]s2 t is1 ! front or re> edges1 or bo?1 are 9 planes oblique to ! axis ( ! cyl9d]4 ,"o ( ^! visor-%ap$ %ields 0 employ$ on ! ,cli*y tunnel4 ,! ,%ell4--,x is absolutely necess>y t ! ext]ior surface ( ! %ell %\ld be smoo?1 & = ?is reason ! ext]ior rivet heads mu/ be c\nt]sunk4 ,x is g5]ally admitt$1 also1 t ! %ell %\ld be p]fectly cyl9drical1 & n conical4 ,! conical =m has "s advantage 9 r$uc+ ! frictional resi/ance to ! advance ( ! %ield2 b ?is is g5]ally consid]$ to be m ?an c\nt]balanc$ by ! dang] ( subsid5ce ( ! e>?1 caus$ by ! excessive void :i* x leaves beh9d ! iron tunnel l9+4 ,= ! same reason ! %ell plate1 :i* ov]laps ! =w>d r+ ( ! l9+1 %\ld be z ?9 z practicable1 b its ?ickness %\ld n be r$uc$ s t x w deflect "u ! e>? pressure f above4 ,g5]ally ! %ell is made ( at lea/ two ?icknesses ( plat+1 ! plates be+ arrang$ s z to break jo9ts1 &1 ?us1 to avoid ! use ( cov] jo9ts1 to int]rupt ! smoo? surface :i* is s ess5tial1 p>ticul>ly on ! ext]ior4 ,! ?ickness ( ! %ell requir$ w v>y ) ! diamet] ( ! %ield1 & ! "* & /r5g? ( ! diametrical brac+4 ,mr4 ,raynald ,lg\ez sugge/s z a rule = det]m9+ ! ?ickness ( ! %ell1 t1 to a m9imum ?ickness ( #b mm41 %\ld be add$ #a mm4 = e met] ( diamet] ov] #d met]s4 ,ref]r+ to ! illu/rations1 ,figs4 #abh to #acb inclusive1 x w be not$ t ! ,/4 ,clair tunnel %ield1 #ba ft4 9 diamet]1 _h a %ell ( #a-;94 /eel plates ) cov]-plate jo9ts & int]ior angle /iff5]s2 ! %ell ( ! ,ea/ ,riv] tunnel %ield1 #aa ft4 9 diamet]1 0 made up ( "o -94 & "o -94 plate2 ! ,blackwall tunnel %ield1 #bg ft4 #i ins4 9 diamet]1 _h a %ell consi/+ ( f\r ?icknesses ( -94 plates2 & ! ,cli*y tunnel %ield1 ) a diamet] ( #b4jf met]s1 _h a %ell #b millimet]s ?ick4 ,front-,end ,con/ruction4--,by ! front end is meant t portion ( ! %ield betwe5 ! cutt+-edge & ! v]tical diaphragm4 ,! l5g? ( ?is portion ( ! %ield 0 =m]ly made q small1 & :]e ! mat]ial p5etrat$ is v s(t1 a %ort front-end con/ruction yet has _m advocates2 b ! g5]al t5d5cy n[ is to ext5d ! cutt+-edge f> en\gh ahead ( ! diaphragm to =m a fair-siz$ work+ *amb]4 ,excavation is f> m easy & rapid :5 ! face c be attack$ directly f 9 front ( ! diaphragm ?an :]e ! "w has to be done f beh9d ?r\gh ! ap]tures 9 ! diaphragm4 ,s long z ! ro( ( ! excavation is support$ f fall+1 exp]i5ce has %[n t x is easily possible to ext5d ! excavation safely "s di/ance ahead ( ! diaphragm4 ,9 reasonably /able mat]ial1 l compact-clay1 ! front face w usually /& alone = ! %ort "t necess>y to excavate ! section & advance ! %ield "o /age4 ,9 s(t] mat]ial ! face c usually be su/a9$ = ! same %ort p]iod by means ( compress$ air2 or ! face ( ! excavation1 in/ead ( be+ made v]tical1 c be all[$ to assume its natural slope4 ,9 ! latt] case a visor-%ap$ front-end con/ruction1 su* z 0 us$ on "s portions ( ! ,cli*y tunnel1 is p>ticul>ly advantage\s4 ,! foll[+ figures %[ ! l5g?s ( ! front ends ( a numb] ( repres5tative tunnel %ields4 ,city & ,s\? ,london #a ft4 ,/4 ,clair ,riv] #aa4be ,hudson ,riv] #e ,m]sey ,riv] #c ,ea/ ,riv] #c ,blackwall #f4e ,two g5]al types ( con/ruction are employ$ = ! cutt+-edge4 ,! fir/ type consi/s ( a ca/-iron or ca/-/eel r+1 bevel$ to =m a *isel-l cutt+-edge & bolt$ to ! ends ( ! =w>d %ell plates4 ,?is con/ruction 0 fir/ employ$ 9 ! %ield = ! ,london ,t[] tunnel1 & has s9ce be5 us$ on ! ,city & ,s\? ,london1 ,wat]loo & ,city1 & ! ,cli*y tunnels4 ,! second con/ruction consi/s 9 brac+ ! =w>d %ell plates by means ( "r triangul> brackets1 ^: p]p5dicul> sides are rivet$ respectively to ! %ell plates & ! diaphragm1 & ^: incl9$ sides slant backw>d & d[nw>d f ! front edge1 & c>ry a conical r+ ( plat+4 ,! %ields = ! ,/4 ,clair ,riv]1 ,ea/ ,riv]1 & ,blackwall tunnels %[ =ms ( ?is type ( cutt+-edge con/ruction4 ,a modification ( ! second type ( con/ruction1 :i* consi/s 9 omitt+ ! conical plat+1 0 employ$ on "s ( ! %ields = ! ,cli*y tunnel4 ,?is modification is g5]ally consid]$ to be all[able only 9 mat]ials :i* h little /ability1 & :i* crumble d[n be=e ! advance ( ! cutt+-edge4 ,:]e ! mat]ial is ( a /icky or compact nature1 into :i* ! %ield 9 advanc+ mu/ actually cut1 ! bevel$ plat+ is necess>y to insure a clean cutt+ action )\t w$g+ or jamm+ ( ! mat]ial4 ,cellul> ,division4--,x is necess>y 9 %ields ( l>ge diamet] to brace ! %ell horizontally & v]tically aga9/ di/ortion4 ,?is brac+ also s]ves to =m /ag+s = ! workm51 & to divide ! %ield into cells4 ,! foll[+ table %[s ! arrangem5t ( ! v]tical & transv]se brac+ 9 sev]al repres5tative tunnel %ields4 ---------------------------------------- --------- ,,"n ,,( ,,tunnel4 ,,diamet]4 ,,hori- ,,plates1 ,,v]t4 ,,zontal4 ,,di/4 ,,braces4 ,,ap>t4 ---------------------------------------- -------- ,ft4 ,94 ,no4 ,ft4 ,no4 ,hudson ,riv] #ai #aa #b #f4ed #b ,cli*y #ai4d #j #b #f4ed ,none ,/4 ,clair ,riv] #ba #f #b #f4ih #c ,wat]loo 7,/ation7#bd #aj #b #g4ab ,none ,blackwall #bg #h #b #f4j #c ,ea/ ,riv] #aa ,none 444 #a ---------------------------------------- -------- ,ref]r+ fir/ to ! horizontal divisions1 x may be not$ t !y s]ve diff]5t purposes 9 diff]5t in/ances4 ,9 ! ,cli*y tunnel %ield ! horizontal divisions =m$ simply work+ plat=ms2 9 ! ,wat]loo tunnel %ield !y 7 design$ to abut closely aga9/ ! work+ face by means ( special jacks1 & s to divide x into ?ree sep>ate divisions2 9 ! ,/4 ,clair tunnel !y s]v$ z work+ plat=ms1 & also _h cutt+-edges = p5etrat+ ! mat]ial ahead2 & 9 ! ,blackwall tunnel %ield !y s]v$ z work+ plat=ms1 & _h cutt+-edges z 9 ! ,/4 ,clair tunnel %ield1 & 9 addition ! middle division 0 s devis$ t ! two l[] *amb]s ( ! %ield c\ld be kept "u a high] pressure ( air ?an ! two upp] *amb]s4 ,pass+ n[ to ! v]tical divisions1 !y s]ve to brace ! %ell ( ! %ield aga9/ v]tical pressures1 & also to divide ! horizontal *amb]s into cells2 b unlike ! horizontal plates !y are n provid$ ) cutt+-edges4 ,! ,/4 ,clair1 ,hudson ,riv]1 & ,blackwall tunnel %ields illu/rate ! use ( ! v]tical brac+ = ! d\ble purpose ( v]tical brac+ & ( divid+ ! horizontal *amb]s into cells4 ,! ,wat]loo tunnel %ield is an example1 ( v]tical brac+ employ$ solely z brac+4 ,! v]tical division ( ! ,ea/ ,riv] tunnel %ield 0 employ$ 9 ord] to all[ ! %ield to be dissembl$ 9 quadrants4 ,! ,diaphragm4--,! purpose ( ! %ield diaphragm is to close ! re> end ( ! %ield & ! tunnel beh9d f an inru% ( wat] & e>? f ! face ( ! excavation4 ,x also s]ves ! second>y purpose ( /iff5+ ! %ell diametrically4 ,/ructurally ! diaphragm sep>ates ! front-end con/ruction previ\sly describ$ f ! re>-end con/ruction1 :i* w be describ$ f>!r on2 & x is usually compos$ ( iron or /eel plat+ re9=c$ by beams or gird]s1 & pi]c$ ) "o or sev]al op5+s by :i* access is _h to ! work+ face4 ,9 /able mat]ial1 :]e cav+ or an inru% ( wat] & e>? is n likely1 ! diaphragm is omitt$4 ,! %ield ( ! ,wat]loo tunnel is an example ( ?is con/ruction4 ,9 m trea*]\s mat]ials1 h[ev]1 n only is a diaphragm necess>y1 b x is also necess>y to dim9i% ! size ( ! op5+s ?r\gh x1 & to provide means = clos+ !m entirely4 ,sometimes only "o or two op5+s are left ne> ! bottom ( ! diaphragm1 z 9 ! ,/4 ,clair & ,m]sey tunnel %ields2 & sometimes a numb] ( small] op5+s are provid$1 z 9 ! ,ea/ ,riv] & ,hudson ,riv] tunnel %ields4 ,9 highly trea*]\s mat]ials subject to sudd5 & viol5t irruptions ( e>? f ! excavation face1 x sometimes is ! case t op5+s1 h[ev] small1 clos$ 9 ! ord9>y mann]1 are impracticable1 & special con/ruction has to be adopt$ to deal ) ! difficulty4 ,! %ields = ! ,m]sey & = ! ,blackwall tunnels are examples ( su* special devices4 ,9 ! ,m]sey tunnel a second diaphragm 0 built beh9d ! fir/1 ext5d+ f ! bottom ( ! %ield upw>d to ab\t half its total height4 ,! ap]ture 9 ! fir/ diaphragm be+ ne> ! bottom1 ! space betwe5 ! second & fir/ diaphragms =m$ a trap to hold ! infl[+ mat]ial4 ,! ,blackwall tunnel %ield1 z previ\sly indicat$1 _h its front end divid$ into cells4 ,ord9>ily ! face ( ! excavation 9 front ( ea* cell 0 left op51 b :]e mat]ial 0 enc\nt]$ :i* irrupt$ into ^! cells a special means ( clos+ ! face 0 necess>y4 ,?is consi/$ ( ?ree pol+-bo>ds or %utt]s ( iron held "o above ! o!r aga9/ ! face ( ! excavation4 ,^! %utt]s 7 support$ by means ( /rong ?read$ rods pass+ ?r\gh nuts fa/5$ to ! v]tical frames1 :i* p]mitt$ ea* %utt] to be advanc$ aga9/ or )drawn f ! face ( ! excavation indep5d5tly ( ! o!rs4 ,v>i\s o!r con/ructions h be5 devis$ to reta9 ! face ( ! excavation 9 highly trea*]\s soils1 b few ( !m h be5 subject$ to conclusive te/s1 & !y d n !re=e ju/ify consid]ation4 ,re>-end ,con/ruction4--,by ! re> end ( ! %ield is meant t portion at ! re> ( ! diaphragm4 ,x may be divid$ into two p>ts1 call$ respectively ! body & ! tail ( ! %ield4 ,! *ief purpose ( ! body ( ! %ield is to furni% a place = ! location ( ! jacks1 pumps1 motors1 etc41 employ$ 9 manipulat+ ! %ield4 ,x also s]ves a purpose 9 di/ribut+ ! weight ( ! %ield ov] a l>ge area4 ,to facilitate ! passage ( ! %ield ar\nd curves1 or 9 *ang+ f "o grade to ano!r1 x is desirable to make ! body ( ! %ield z %ort z possible4 ,9 ! ,m]sey1 ,cli*y1 & ,wat]loo tunnel %ields1 &1 9 fact1 9 mo/ o!rs :i* h be5 employ$1 ! %ell plates ( ! body h be5 re9=c$ by a heavy ca/-iron r+1 )9 & to :i* are atta*$ ! jacks & o!r app>atus4 ,! late/ op9ion1 h[ev]1 seems to po9t to ! use ( brackets & beams = /r5g!n+ ! %ell = ! purpose nam$1 r ?an to ?is heavy ca/-iron con/ruction4 ,9 ! ,hudson ,riv]1 ,/4 ,clair ,riv]1 & ,ea/ ,riv] tunnel %ields1 ) _! long & /rongly brac$ front-end con/ruction to c>ry ! jacks1 ! body ( ! %ield1 s to speak1 is omitt$ & ! re>-end con/ruction consi/s simply ( ! tail plat+4 ,9 ! ,blackwall %ield1 ! body ( ! %ield %ell provides ! space necess>y = ! d\ble diaphragms & ! cells :i* !y inclose4 ,9 a g5]al way1 x may be said t ! pres5t t5d5cy ( eng9e]s is to favor z %ort & z light a body con/ruction z c be secur$4 ,! tail ( ! %ield s]ves to support ! e>? :ile ! l9+ is be+ erect$2 & = ?is reason x ov]laps ! =w>d r+ ( ! l9+1 z %[n cle>ly by mo/ ( ! %ields illu/rat$4 ,to fulfill ?is purpose1 ! tail-plates %\ld be p]fectly smoo? inside & outside1 s z to slide easily betwe5 ! outside ( ! l9+ plates & ! e>?1 & %\ld also be z ?9 z practicable1 9 ord] n to leave a l>ge void beh9d ! l9+ to be fill$ 94 ,9 soils :i* are fairly /able1 ! tail con/ruction is (t5 visor-%ap$2 t is1 ! tail-plates ov]lap ! l9+ only =1 say1 ! ro( f ! spr++ l9es up1 z 9 "o ( ! %ields = ! ,cli*y tunnel4 ,9 un/able mat]ials ! tail-plat+ ext5ds entirely ar\nd ! %ield & excavation4 ,! l5g? ( ! tail-plat+ is usually suffici5t to ov]lap two r+s ( ! l9+1 b 9 "o ( ! ,cli*y tunnel %ields x w be notic$ t x ext5d$ ov] ?ree r+s ( l9+4 ,?is seem+ly consid]able space = ?9 /eel plates is made possible by ! fact t ! extreme re> end ( ! tail always re/s ^u ! la/ complet$ r+ ( l9+4 ,9 clos+ ^! rem>ks conc]n+ ! re>-end con/ruction1 ! accompany+ table1 prep>$ by ,mr4 ,raynald ,lg\ez1 w be ( int]e/1 z a g5]al summ>y ( pr9cipal dim5sions ( mo/ ( ! important tunnel %ields :i* h be5 built4 ,! figures 9 ?is table h be5 conv]t$ f metric to ,engli% measure1 & "s slight v>iation f ! exact dim5sions necess>ily exi/s4 ,! diff]5t columns ( ! table %[ ! diamet]1 total l5g?1 & ! l5g? ( ea* ( ! ?ree pr9cipal p>ts into :i* tunnel %ields are ord9>ily divid$ 9 con/ruction z previ\sly describ$3 ---------------------------------------- ---------------- ,,l5g? ,,9 ,,feet4 ,,"n ,,( ,,%ield4 ------------------------------- ,,diamet]4,,tail4,,body4,,front4,,total4 ---------------------------------------- ------------ ,concorde ,siphon #f4ge #b4ea #b4ee #a4af #f4fg ,cli*y ,siphon #h4ci #b4ea #b4ee #a4af #f4af ,m]sey #i4ig #e4fa #b4ih #b4ih #aa4eh ,ea/ ,riv] #aj4ii #c4ea #j4cb #c4fg #g4ea ,city & ,s\? ,london #aj4ii #b4fe #b4hb #a4ja #f4di ,glasg[ ,di/rict #ab4jg #b4fe #b4hb #a4ja #f4di ,wat]loo & ,city #ab4ii #b4ge #b4ih #a4bd #f4ih ,glasg[ ,h>bor #ag4be #b4ge #b4ih #a4jh #h4di ,hudson ,riv] #ai4ia #d4hb #b4ih #e4fg #aj4di ,/4 ,clair ,riv] #ba4eb #d4jj #b4ih #aa4be #ae4be ,cli*y ,tunnel #bc4g-ai4h #d4jj #b4ih #f4hh #ag4bb ,cli*y ,tunnel #bc4h-ai4d #g4ddaa4ij #d4df #bc4fe ,blackwall #bg4jj #f4ih #e4ij #f4ei #ai4dh ,wat]loo ,/ation #bd4hf #c4cd #e4ea #a4ad #aj4jj ---------------------------------------- ------------ ,a %ield ( #fj or #ajj tons weight c h>dly be direct$ along ! l9e ( ! propos$ tunnel & also ?r\gh curves & grades1 especially :5 driv5 ?r\gh loose or muddy soils4 ,! tunnels ( ! ,new ,york & ,hudson ,riv] ,railroad "u ! ,hudson1 & ! tunnel ( ! ,new ,york ,rapid ,transit ,railway "u ! ,ea/ ,riv]1 %[ m>k$ evid5ce ( h[ tr\blesome ?is "w is4 ,to avoid ^! & o!r inconv5i5ces enc\nt]$ 9 e %ield1 ! ,au?or has design$ a new %ield :i* 0 briefly describ$ at page #bea4 ,illu/ration3 ,,fig4 #acf4--;,elevation & ,section ( ,hydraulic ,jack1 ,ea/ ,riv] ,gas ,tunnel4 ,jacks4--,! motive p[] usually employ$ 9 driv+ mod]n tunnel %ields is hydraulic jacks4 ,9 "s ( ! e>li] %ields screw-jacks 7 us$1 b ^! soon gave way to ! m p[]ful hydraulic device4 ,! mann] ( atta*+ ! hydraulic jacks to ! %ield is always to fa/5 ! cyl9d] ca/+s at regul> int]vals ar\nd ! inside ( ! %ell1 ) ! pi/on rods ext5d+ backw>d to a be>+ aga9/ ! =w>d edge ( ! l9+4 ,9 ! old] =ms ( %ield1 hav+ an int]ior ca/-iron re9=c+ r+ con/ruction1 ! jack cyl9d] ca/+s 7 always atta*$ to ?is ca/-iron r+2 b 9 _m ( ! lat] %ields con/ruct$ )\t ?is ca/-iron re9=c+ r+1 ! cyl9d] ca/+s are atta*$ to ! %ell by means ( bracket & gusset connections4 ,! numb] & size ( ! jacks employ$1 & ! di/ance ap>t at :i* !y are spac$1 dep5d ^u ! size ( ! %ield & ! "* ( ! mat]ial 9 :i* x is design$ to "w4 ,9 /iff & comp>atively /able clays1 ! sk9 friction ( ! %ield is comp>atively small1 & an aggregate jack-p[] ( f #d to #e tons p] squ>e y>d ( ! ext]ior friction surface ( ! %ield has usually be5 f\nd ample4 ,! cyl9d]s are spac$ ab\t #e ft4 ap>t1 & h a work+ diamet] ( f #e to #f ins41 ) a wat] pressure ( ab\t #ajjj lbs4 p] sq4 94 ,9 s(t1 /icky mat]ial1 giv+ a high sk9 friction1 ! aggregate jack-p[] requir$ p] squ>e y>d ( ext]ior %ell surface rises to f #ah to #bd tons2 ! jacks are spac$ ab\t #c ft4 ap>t2 & ! work+ cyl9d] diamet] & wat] pressure are1 respectively1 ab\t #f or #g ins41 & f #djjj lbs4 to #fjjj lbs4 p] sq4 94 ,) ^! high pressures1 p[] pumps are necess>y to give ! requir$ wat] pressure2 b :]e ! pressure requir$ does n exce$ #ajjj lbs4 p] sq4 941 h& pumps may be1 & usually are1 employ$4 ,fig4 #acf %[s ! hydraulic jacks us$ 9 ! ,ea/ ,riv] ,gas ,tunnel at ,new ,york4 ,! numb] ( jacks requir$ dep5ds ^u ! diamet] ( ! %ield1 &1 ( c\rse1 ^u ! di/ance ap>t :i* !y are plac$4 ,9 ! ,city & ,s\? ,london tunnel %ield six jacks 7 us$1 & 9 ! ,blackwall %ield #bd 7 us$4 ,! me*anical con/ruction ( ! jacks = tunnel %ields pres5ts no features out ( ! usual l9es ( su* devices us$ else:]e4 ,! jacks us$ on ! ,ea/ ,riv] tunnel %ield are %[n by ,fig4 #acf4 ,two g5]al me?ods are employ$ = transmitt+ ! ?ru/ ( ! pi/on rods aga9/ ! tunnel l9+4 ,! object s\ght 9 ea* is to di/ribute ! ?ru/ 9 su* a mann] t !re is no dang] ( b5d+ ! ?9 front flange ( ! =w>d l9+ r+4 ,9 ,engli% practice ! plan usually adopt$ is to atta* a %oe or be>+ ca/+ to ! end ( ! pi/on rod1 :i* w di/ribute ! pressure ov] a consid]able area4 ,an example ( ?is con/ruction is ! %ield = ! ,city & ,s\? ,london tunnel4 ,9 ! ,ea/ ,riv] & ,/4 ,clair ,riv] tunnels built 9 ,am]ica1 ! tail ( ! pi/on rod is s con/ruct$ t ! ?ru/ is c>ri$ directly to ! %ell ( ! l9+4 ,,l9+4 ,ei!r iron or masonry may be us$ = l9+ %ield-driv5 tunnels b pres5t practice is almo/ univ]sally 9 favor ( iron l9+4 ,z usually built1 iron l9+ consi/s ( a s]ies ( successive ca/-iron r+s1 ! abutt+ edges ( :i* are provid$ ) flanges4 ,^! flanges are connect$ by means ( butts1 ! jo9ts be+ pack$ ) ?9 /rips ( wood1 oakum1 cem5t1 or "s o!r mat]ial to make !m wat]-tight4 ,ea* l9+ r+ is made up ( f\r or m segm5ts1 :i* are provid$ ) flanges = bolt$ connections simil> to ^? fa/5+ ! successive r+s4 ,g5]ally ! cr[n segm5t is made consid]ably %ort] ?an ^? =m+ ! sides & bottom ( ! r+4 ,! erection ( ! iron segm5ts =m+ ! successive r+s ( ! l9+ may be done by h& 9 tunnels ( small diamet] :]e ! weights to be h&l$ are comp>atively light1 b 9 tunnels ( l>ge size special cranes atta*$ to ! %ield or c>ri$ by ! f9i%$ l9+ are employ$4 ,! con/ruction ( ! iron l9+ = ! ,hudson ,riv] tunnel is illu/rat$ 9 ,*apt] ,,xx41 & t = ! ,/4 ,clair ,riv] tunnel is %[n by ,fig4 #acg4 ,illu/ration3 ,"p ,transv]se ,section4 ,longitud9al ,section4 ,,fig4 #acg4--;,ca/-,iron ,l9+1 ,/4 ,clair ,riv] ,tunnel4 ,,*apt] ,,xx4 ,,subm>9e ,,tunnel+ 7,cont9u$74 ,,! ,,%ield ,,& ,,compress$ ,,air ,,me?od4 ,,! ,,hudson ,,riv] ,,tunnel ,,( ,,! ,,p5nsylvania ,,railroad4 ,! %ield & compress$ air me?od ( excavat+ subaque\s tunnels is us$ :5 ! di/ance is small betwe5 ! ro( ( ! tunnel & ! b$ ( ! riv]4 ,^! tunnels are usually driv5 f ! %afts sunk f ea* %ore4 ,x is v seldom !y c be driv5 also by an int]m$iate %aft4 ,?is1 h[ev]1 0 done 9 ! case ( ! ,belmont tunnel "u ! ,ea/ ,riv]4 ,"h ! tunnels pass$ "u ! man-(-w> reef :]e a work+ %aft 0 sunk4 ,! plant is locat$ at "s conv5i5t po9t ne> ! head %aft4 ,x consi/s ( a set ( boil]s to provide ! p[] = ! diff]5t ma*9es4 ,!y are l[ & high pressure compressors1 ! =m] supply ! air ?r\gh ! tunnel2 ! latt]1 ! air = work+ ! drills1 9 case rock is enc\nt]$1 & p[] = haul+ & hoi/+ purposes4 ,! v>i\s pumps =ce ! wat] = ! hydraulic rams t drive ! %ield & "w ! erector4 ,!y also remove ! wat] f ! tunnel :i* always collects 9 v>iable quantities at ! bottom ( ! excavation4 ,besides ! ma*9es = light & v5tilation purposes1 ! head %aft is provid$ ) an ov]head con/ruction :]e are h\s$ ! hoi/+ ma*9es1 ! telephone & o!r means ( communication ) ! "w at ! front4 ,usually a long tre/le is built 9 connection ) ! head %aft1 lead+ to ! dump+ place & y>d4 ,on ?is incl9$ elevat$ /ructure are locat$1 also1 ! tracks ^u :i* w run ! small c>s us$ inside ! tunnel = haul+ purposes4 ,! %afts are excavat$ on a squ>e1 rectangul> or circul> plan & are usually l9$ ) masonry4 ,x is only rec5tly t %afts excavat$ ?r\gh loose soils h be5 l9$ ) ! same ca/-iron l9+ us$ 9 ! tunnels1 ! only diff]5ce be+ t ! r+s 7 laid flat on ! gr\nd & atta*$ to ^? already sunk4 ,aft] ! %aft has be5 sunk to ! requir$ level1 ! tunnel is driv5 t[>d ! riv] by any "o ( ! me?ods us$ = l& "w4 ,at "s conv5i5t di/ance f ! %aft1 ! dim5sions ( ! tunnel are enl>g$ = a l5g? ( #bj or #cj ft4 ,9 ?is l>g] space1 call$ ! %ield *amb]1 ! %ield is assembl$1 m\nt$1 &1 :5 complet$1 x is sl[ly pu%$ t[>d ! riv]4 ,! tunnel is excavat$ f ! %ield *amb] on1 ) dim5sions equal to ! ext]ior %ell ( ! %ield4 ,! con/ruction ( ! %ield & ! hydraulic jacks us$ = its advance are expla9$ 9 a prec$+ *apt]4 ,9 v loose soils1 a solid bulkhead ( masonry is built across ! tunnel1 aft] ! %ield has advanc$ to a c]ta9 di/ance & "s r+s ( ! ca/-iron l9+ h be5 erect$4 ,! bulkhead is provid$ ) ?ree air locks--two ne> ! floor ( ! tunnel1 = work+ purposes1 & "o ne> ! ro(1 call$ ! em]g5cy lock1 :i*1 z ! "n sugge/s1 is us$ only 9 case ( dang]4 ,! air locks are /eel cyl9d]s f #aj to #ae ft4 long & #f ft4 9 diamet]1 made up ( boil] plates4 ,!y are provid$ ) doors at ea* end1 besides ! pipes = ! admission & exit ( compress$ air4 ,! work+ locks also h n>r[-gauge tracks = haul+ purposes4 ,9 rock or m consi/5t soil ! bulkhead is con/ruct$ aft] ! %ield is f> ahead1 s9ce !re is no imm$iate necessity1 "u ^! conditions1 to use ! compress$ air4 ,9 bo? ! loose & good soils1 :5 ! %ield has be5 advanc$ ov] #ejj ft4 f ! bulkhead1 a second bulkhead1 ) air locks1 is erect$ 9 ! tunnel4 ,! fir/ is left 9 place b us$ only 9 case ( em]g5cy4 ,to direct ! %ield along ! c5t] l9e & ?r\gh curves & grades1 accurate measurem5ts are tak51 & ! di/ance betwe5 ! %ield & ! la/ r+ ins]t$ 9 ! iron l9+ is regulat$ accord+ly4 ,! alignm5t inside ! tunnel is ma9ta9$ 9 a v simple way4 ,= ?is purpose1 po9ts correspond+ to ! c5t] l9e are m>k$ on ! ro( at di/ances ( #ajj ft4 ,ne>ly #ajj ft4 f ! %ield1 a transit is set up on a /rong scaffold spann+ ! tunnel1 & x is support$ by ! flanges ( ! iron l9+4 ,a plumb-l9e is hung f "o ( ! po9ts ( ! ro( already det]m9$1 z indicat+ ! c5t] l9e2 & ! transit man aligns 8 in/rum5t ) ?is plumb-l9e2 aft] ?is he 8plunges0 8 telescope4 ,a rodman next places a horizontal rod ( special con/ruction betwe5 ! flanges ( ! la/ r+ ( ! l9+4 ,?is rod has 9 ! c5t] an op5 slot :i* c>ries a glass ) a black v]tical l9e4 ,! slot is graduat$1 ! z]o ( graduation rema9s 9 ! c5t] :ile ! v]tical l9e is mov$ "r & left4 ,! rodman places a lamp beh9d ! slot & ! transit-man tells him h[ to move ! d>k l9e until x co9cides ) ! axis ( ! tunnel4 ,if ! r+1 j erect$1 be a little out ( alignm5t1 x is readju/$ by pu%+ ! %ield a little m on ! side t has sw]v$ f ! axis ( ! tunnel4 ,z ! %ield is pu%$ =w>d1 x is kept 9 place by f\r m5 ) graduat$ rods1 "o man on ea* side ( ! %ield1 "o on top & ! o!r on ! floor4 ,z ! %ield progresses1 !y repeat al\d 9 succession1 ! di/ance indicat$ on ! rods1 :i* is ! di/ance f ! %ield to ! out] circumf]5tial flange ( ! la/ r+ ( ! l9+4 ,:5 an advance ( "o foot has be5 made1 read+s are tak5 at e in*2 & :5 v ne> ! requir$ di/ance1 !y are tak5 at e qu>t] ( an in*4 ,9 ?is way x is n difficult to br+ ! %ield back into l9e1 9 case x may h %ift$ a little to ! "r or left4 ,:5 curves are met1 ! r+s are no long] cyl9drical segm5ts b tores1 s t ! segm5ts at "o side are long] ?an ^? on ! o!r4 ,9 ?is case1 ! %ield is advanc$ m on "o side by a quantity equal to ! diff]5ce ( ! two sides ( ! r+ to be erect$4 ,at ea* advance ! %ield is mov$ #b ft4 or #b ft4 ahead1 ! di/ance correspond+ to ! l5g? ( ! ca/-iron r+s ( ! l9+4 ,)9 ! space n[ op5 betwe5 ! %ield & ! l9+ ano!r r+ is ins]t$4 ,! r+ is compos$ ( diff]5t segm5ts provid$ ) flanges & holes bor$ s !y c be bolt$ toge!r4 ,! segm5ts ( ! l9+ are v heavy & difficult to h&le b !y are easily set by means ( ! erector4 ,:5 ! erector is n m\nt$ on ! %ield1 x is locat$ 9 ! middle ( a gird] plac$ across ! iron r+s ( ! l9+ & j at ! re> end ( ! %ield4 ,! gird]1 at bo? extremities1 has flang$ :eels re/+ on rails :i* are plac$ on brackets4 ,^! brackets are atta*$ tempor>ily to ! flanges ( ! iron l9+4 ,! erector is provid$ ) an arm capable to sw+ 9 a full circle4 ,its movem5ts are regulat$ by two hydraulic jacks1 locat$ horizontally on ! spann+ gird]4 ,on ! extreme end ( ! revolv+ arm are projections ) holes = ! bolts4 ,ea* segm5tal plate ( ! l9+ has a k9d ( plug 9 ! c5t] :i* is ca/ toge!r ) ! plate & is provid$ ) holes = ! bolt4 ,9 plac+ ! segm5tal plates ( ! l9+1 ! arm ( ! erector is swung ov] ! plate to be lift$1 !n two bolts are pass$ ?r\gh ! holes 9 ! projection ( ! erector1 & ?r\gh ^? 9 ! plug4 ,! arm ( ! erector is !n mov$ upw>ds until ! plate1 free f all ob/acles1 is swung v ne> its int5d$ position4 ,!re x is adju/$ & held until bolts are ins]t$ to fix x to ! plates ( ! prec$+ r+4 ,9 connection ) ! me?od ( excavat+ subm>9e tunnels by means ( %ield & compress$ air1 ! excavation v>ies ) ! quality ( soil enc\nt]$4 ,9 compact rock ! usual head+ & b5* me?od1 s common 9 l& tunnels1 is also employ$ 9 ?is case4 ,! %ield is left beh9d 9 pres5ce ( good rock4 ,! m5 at ! front attack ! rock ) air drill+ ma*9es & *>ges ( dynamite4 ,! holes are driv5 at a small] dep? ?an 9 l& "w2 v light *>ges ( dynamite are us$ & only a few holes fir$ at ea* r\nd4 ,e precaution is tak5 9 ord] n to di/urb ! %ield & ! b$ ( ! riv] any m ?an is possible1 because at a %all[ dep? ! bla/ w\ld t5d to wid5 ! exi/+ crevices 9 ! rock & ?us p]mit an infl[ ( wat]4 ,:5 ! rock is fissur$ or dis9tegrat$ & ! ro( ( ! excavation at ! front requires timb]+1 ! %ield %\ld be kept clos] to ! front4 ,9 ?is way ! quantity ( timb] = /rutt+ is greatly r$uc$1 s less5+ ! probabilities ( fires4 ,x is v difficult1 9 compress$ air1 to ext+ui% fires & 9 almo/ e in/ance ! only way is to flood ! tunnel4 ,?is 0 done at ! ,manhattan end ( ! tunnel "u ! ,ea/ ,riv] = ! ext5sion to ,brooklyn ( ! ,new ,york ,subway4 ,! excavation is made by h& 9 loose b compact soils su* z clay4 ,! m5 "w on plat=ms locat$ at ! front ( ! %ield & !y are protect$ f ! cav+-9 ( ! ro( by a hood add$ = work+ ?r\gh loose soils4 ,! m5 excavate ! mat]ial :i* is %ovel$ inside ! tunnel & is c>ri$ away 9 small c>s4 ,! %ield is v close to ! front ( ! excavation 9 loose soil4 ,! ,ea/ ,bo/on tunnel1 "u ,bo/on ,h>bor1 connect+ ) ! ,bo/on ,subway1 0 excavat$ ?r\gh blue clay4 ,! m9imum di/ance betwe5 ! bottom ( ! wat] & ! ro( ( ! excavation 0 #ah ft4 ,! tunnel 0 excavat$ by means ( compress$ air & ! %ield :i* 0 only us$ = ! ro(4 ,x slid on top ( concrete side walls built 9 two drifts :i* 7 excavat$ ne>ly #ajj ft4 ahead ( ! %ield4 ,! tunnel 0 l9$ ) concrete1 ! ar* be+ re9=c$ by longitud9al /eel rods :i* receiv$ ! ?ru/ ( jacks us$ = advanc+ ! %ield4 ,! mat]ial 9 ! drifts "u ! %ield & ! b5* 0 remov$ by h& & c>ri$ away 9 small c>s4 ,subaque\s tunnels driv5 ?r\gh v loose soils c be excavat$ by simply leav+ ! doors op5 :ile ! %ield is pu%$ ahead4 ,! mat]ial1 dislodg$ by ! cutt+ edge ( ! %ield1 is =c$ ?r\gh ! doors & falls on ! floor :5ce x is remov$ 9 small c>s4 ,9 v loose soils ! excavation has be5 made 9 a /ill m economic way2 ! %ield ) clos$ doors is simply squeez$ ?r\gh ! soil4 ,?is me?od is f9ancially conv5i5t1 because all ! excavat+ & haul+ op]ations are elim9at$ & ! tunnel progresses f #dj to #ej ft4 p] day1 b cle>ly indicates a lack ( /ability4 ,9 ?is mann]1 ! ,hudson ,riv] tunnel ( ! ,new ,york & ,new ,j]sey ,railroad 0 con/ruct$4 ,! pressure ( ! air 9 ! tunnel dep5ds ^u ! dep? & z a rule x v>ies betwe5 #bj & #dj or ev5 m p\nds p] squ>e in* above atmosph]ic pressure4 ,work+ 9 compress$ air causes a peculi> disease commonly kn[n z 8b5ds0 or 8caisson disease0 (t5 prov+ fatal4 ,to prev5t & rem$y ! disease1 ! eng9e]s %\ld ord] a set ( rules to be /rictly obs]v$4 ,! prev5tative measures %\ld be1 fir/1 to employ only sob]1 /rong & heal?y m51 nev] "o :o has n successfully pass$ ! exam9ation ( ! att5d+ physician2 second1 to ord] ! lock t5d]s nev] to all[ any man 9 or out ( ! tunnel unless he has sp5t at lea/ t5 m9utes )9 ! locks4 ,bo? compression & decompression %\ld be ?or\gh & x _c be 9 less ?an ?is "t4 ,a /op ( only a few m9utes 9 ! locks is n suffici5t & ?is incomplete compression or decompression is ! real cause ( ! b5ds4 ,! m5 become c>eless aft] !y h be5 9 ! compress$ air = "s "t1 & !y try to r$uce ?is tiresome op]ation to a m9imum1 h5ce ! duty ( ! eng9e] to /rictly en=ce ?is rule4 ,! rem$ial measures %\ld consi/ ( con/ant m$ical att5dance ne> ! %afts & ! erection ( a compress$ air hospital :]e ! m5 affect$ by b5ds = lack ( decompression may be att5d$ & cur$4 ,,! ,,hudson ,,riv] ,,tunnels ,,( ,,! ,,p5nsylvania ,,railroad4#ac ,! tunnels con/ruct$ "u ! ,hudson ,riv] = ! ,p5nsylvania ,railroad1 consi/ ( two p>allel tubes driv5 side by side #ad ft4 ap>t4 ,! tubes are ( circul> cross-section1 #bc ft4 ext]ior diamet]1 & are l9$ ) ca/-iron r+s4 ,! tunnels 7 driv5 f two %afts1 "o on ! ea/]n %ore ( ! ,hudson ,riv] ne> #cbnd ,/4 & #aa? ,ave41 ,new ,york2 ! o!r at ,weehawk51 ,new ,j]sey1 ne> ! pi]s ( ! ,erie ,railroad4 ,! horizontal di/ance betwe5 ! %afts 0 #feej ft4 ,! p]man5t "o at ,weehawk5 0 built on a squ>e plan1 #acj ft4 to a side4 ,x 0 l9$ ) concrete masonry & ! walls 7 batt]$ 9 su* a way z to become ! %ape ( an inv]t$ fru/um ( a pyramid4 ,x 0 provid$ ) five op5+s at ! bottom1 f\r ( ^! are us$ by tra9s t run 9 ! op51 ! fif? "o leads to a p[] h\se ne> by4 ,dur+ ! con/ruction ( ! tunnels "o-?ird ( ?is %aft 0 us$ = ! l& portion ( ! tunnel "u ,b]g5 ,hill1 :ile ! rema9+ two-?irds 7 devot$ to ! con/ruction ( ! tunnel "u ! riv]4 ,! work+ %aft on ,manhattan ,isl& 0 a side %aft ( rectangul> plan #cj ft4 by #bb ft41 ! tunnel prop] be+ connect$ by two drifts #aj ft4 by #aj ft4 ea*4 ,! %ield rooms #bc ft4 long1 7 situat$ on bo? sides ( ! riv] j 9 front ( ! %afts4 ,on ! ,new ,york side1 ! %ields1 "o = ea* tube1 7 built inside ! iron l9+ ( ! %ield *amb]1 & ! hoi/+ tackle 0 slung f ! iron l9+4 ,! erection on ! ,weehawk5 side 0 done 9 ! b>e rock excavation :]e timb] falsework 0 us$4 ,aft] ! %ields 7 f9i%$ & 9 position1 ! fir/ two r+s ( ! l9+ 7 erect$ 9 ! tail ( ! %ield4 ,^! r+s 7 firmly brac$ to ! rock & ! *amb] l9+2 !n ! %ields 7 %ov$ ahead by _! own jacks1 ano!r r+ 0 built & s on4 #ac ,cond5s$ f pap] by ,james ,=gie1 8,eng4 ,news10 ,vol4 ,,lvi1 & by ,h4 ,b4 ,hewett & ,w4 ,l4 ,br[n1 8,proc4 ,am4 ,soc4 ,c4 ,e401 ,vol4 ,,xxxvi4 ,illu/ration3 ,re> ,elevation ( ,%ield4 ,v]tical ,section4 ,half ,section ,a-,b4 ,half ,section ,c-,d4 ,horizontal ,section4 ,,fig4 #ach4--;,g5]al ,elevations & ,sections ( ,%ield4 ,%ield4--,! %ields us$ 9 ^! tunnels 7 design$ by ,mr4 ,james ,=gie1 ,m4 ,in/4 ,c4 ,e4 & ,m4 ,am4 ,soc4 ,c4 ,e41 & 7 provid$ ) ?ree innovations3 ! segm5tal doors1 ! slid+ plat=ms & ! removable hood4 ,! %ields1 ,fig4 #ach1 7 circul>1 #bc ft4 #f ins4 9 ext]nal diamet]1 & 7 #af ft4 long1 exclusive ( ! hood4 ,! tail ( ! %ield ov]lapp$ ! l9+1 ! maximum be+ #f ft4 #d ins4 dur+ ord9>y work+2 ! m9imum1 #b ft4 dur+ ! op]ation ( tak+ any ram out = repair+4 ,! %ields _h only "o transv]se bulkhead made up ( two cont9u\s horizontal plat=ms & ?ree v]tical p>titions /iff5+ angul> web plates =e & aft ! ram *amb]s4 ,!y 7 connect$ by angles & sk9 plates :i* =m$ a r+-%ap$ frame #be ins4 ?ick radially & ne>ly #e ft4 long4 ,betwe5 ! v]tical & horizontal p>titions 7 left op5+s :i* ei!r 7 p>tially or entirely clos$ by segm5tal doors pivot$ on an axis p>allel to ! face ( ! %ield bulkhead4 ,!re 7 n9e ( su* op5+s on ea* %ield1 ! cle> wid? be+ #b ft4 #g ins41 ! height v>y+ f #b ft4 #b ins4 to #c ft4 #d ins41 accord+ to ! location4 ,! hood at ! front ( ! %ield 0 design$ s z to be deta*$ und]gr\nd & 0 made ( complete segm5ts to p]mit easy erection or deta*m5t4 ,! hood 0 ext5d$ z f> z ! upp] plat=m1 ?us protect+ only ! ro( ( ! excavation4 ,x 0 atta*$ to ! %ield by means ( bolts1 &1 :5 remov$1 x 0 replac$ by ! ca/-/eel cutt+-edge1 built 9 #bd sections & plac$ all ar\nd ! %ield4 ,! eight slid+ plat=ms1 ano!r *>act]i/ic ( ?is %ield1 c\ld be ext5d$ #b ft4 #i ins4 9 front ( ! %ield by means ( hydraulic rams1 &1 :5 s ext5d$1 7 able to /& a pressure ( #gijj lbs4 p] sq4 ft4 ,^! slid+ plat=ms 7 us$ z hoods = ! protection ( ! m5 work+ ?r\gh loose soils1 :ile 9 rock !y enabl$ ! drill+ & bla/+ to be c>ri$ on at ?ree levels4 ,a wat] trap or bird f\nta9 0 con/ruct$1 at ! re> ( ! bulkhead ( ! %ield1 by means ( angle irons to :i* /eel plates 7 bolt$4 ,! op5+ to ! face 0 s spaci\s t 9 an em]g5cy ! m5 c\ld readily escape by gett+ ov] ?is trap into safety4 ,besides1 ) ! assi/ance ( compress$ air1 x 0 suffici5t to p]fectly trap ! wat]-be>+ gr\nd1 9 case ! face collaps$4 ,includ+ rams & erector1 ! total weight ( ! %ield 0 #aic tons4 ,hydraulic ,rams4--,! %ield 0 op]at$ by hydraulic pressure4 ,! ma*9es 7 design$ = a maximum pressure ( #ejjj lbs41 to a m9imum ( #bjjj lbs41 :ile ! av]age work+ pressure 0 #cejj lbs4 p] sq4 94 ,! =w>d movem5t ( ! %ield 0 obta9$ by means ( #bd s+le-act+ rams #h 94 9 diamet] & ) #ch 94 /roke4 ,ea* ram ex]t$ a pressure ( ne>ly #ajj tons1 s t ! comb9$ action ( ! #bd rams 0 equal to #bdjj tons4 ,ea* slid+ plat=m 0 op]at$ by two s+le-act+ rams #c ins4 9 diamet] & ) #b ft4 #i 94 /roke4 ,! rams 7 atta*$ to ! re> face ( ! %ield & ! front ends ( ! cyl9d]s to ! front ends ( ! slid+ plat=ms1 & s9ce ! cyl9d]s 7 movable & free-slid+ s also 7 ! plat=ms4 ,erector4--,! erector1 a box-%ap$ frame m\nt$ on a c5tral %aft1 revolv$ 9 be>+s atta*$ to ! %ield4 ,inside ?is frame !re 0 a diff]5tial hydraulic plung] ( #d 94 & #c 94 diamet]s & #dh 94 /roke4 ,to ! plung] head 7 atta*$ two *annels :i* slide inside ! box frame & to ! project+ ends ( :i* ! grip 0 atta*$4 ,at ! opposite end ( ! box frame 0 atta*$ a c\nt]-weight :i* balances ab\t #gjj lbs4 ( ! tunnel segm5t at #aa ft4 radius4 ,! erector 0 revolv$ by two s+le-act+ rams fix$ horizontally to ! back ( ! %ield1 above ! erector pivot1 ?r\gh d\ble *a9s & *a9 :eels :i* 7 key$ to ! erector %aft4 ,air ,locks4--,two bulkhead walls1 =m+ ! re> closure ( ! pneumatic sections1 7 built 9 ea* end ( ea* tunnel1 "o j ahead ( ! %ield *amb]1 ! o!r ab\t #abjj ft4 ahead ( ! fir/4 ,! walls 7 built ( ,portl& concrete #aj ft4 ?ick1 & !y 7 gr\t$ ) ,portl& cem5t1 "u a pressure ( ne>ly #ajj lbs4 p] sq4 941 to make !m ?or\ghly air-tight4 ,ea* wall _h 9 x ?ree locks2 = man1 mat]ial & em]g5cy4 ,ea* 0 equipp$ ) h& valves arrang$ to be op]at$ f ei!r out] end or f )94 ,! floors ( ! man & mat]ial locks 7 on a level ) ! work+ plat=m ( ! tunnel1 ab\t #c ft4 #f ins4 above ! inv]t2 ! floor ( ! em]g5cy lock 0 ab\t #e ft4 above ! horizontal axis ( ! tunnel4 ,! locks 7 made ( /eel plates & %apes1 ) iron fitt+s rivet$ & bolt$ toge!r4 ,! man lock 0 #aa ft4 long ( elliptical cross-section1 #f ft4 v]tical diamet] & #e ft4 horizontal2 ! mat]ial lock 0 #be ft4 long1 ) circul> cross-section1 #g ft4 diamet]1 & ! em]g5cy lock 0 #bj ft4 long1 ( elliptical cross-section1 #d ft4 v]tical & #c ft4 horizontal diamet]s4 ,fig4 #aci %[s ! elevation ( ! air lock us$ 9 ! ,p5nsylvania tunnel4 ,illu/ration3 ,sectional ,elevation ,horizontal ,section ,,fig4 #aci4--,plan & ,elevation ( ,fir/ ,bulkhead ,wall 9 ,s\? ,tube ,manhattan4 ,excavation4--,9 driv+ ^! tunnels almo/ any k9d ( mat]ial 0 enc\nt]$1 viz41 rock1 p>tly rock1 & p>tly loose soil1 s& & gravel1 & f9ally silt4 ,rock4--,mu* ( ! rock excavation 0 made be=e ! %ields 7 erect$ 9 ord] to avoid ! h&l+ ( rock ?r\gh ! n>r[ op5+s ( ! %ield doors4 ,?r\gh\t ! cross-section ! %ield travel$ on a cradle ( concrete 9 :i* #b or #c /eel rails 7 imb$d$4 ,at ! po9ts :]e ! excavation _h be5 made = ! full section ( ! tunnel1 x 0 only necess>y to trim (f ! project+ corn]s ( rock4 ,:]e only ! bottom head+ _h be5 driv5 ! excavation 0 complet$ j 9 front ( ! %ield2 ! drill+ bel[ ! axis level be+ done f ! head+ itself1 & above t f ! front slid+ plat=ms ( ! %ield4 ,! holes 7 plac$ ne> toge!r & 7 drill$ %ort2 v light *>ges ( p[d] 7 us$ 9 ord] to less5 ! *ance ( knock+ ! %ield ab\t too mu*4 ,mix$ ,face4--,:5 ! rock dipp$ to su* an ext5t t ! front ( ! tunnel 0 excavat$ p>tly 9 rock & p>tly 9 loose soil1 ! compress$ air 0 turn$ on1 />t+ ) a pressure v>y+ f #ab to #ah lbs4 ,:5 ! surface ( ! rock 0 p5etrat$1 ! s(t face 0 held up at fir/ by horizontal bo>ds brac$ f ! %ield until ! %ield 0 %ov$4 ,! braces 7 !n tak5 out &1 aft] ! %ield _h be5 %ov$1 7 replac$ by o!rs4 ,z ! am\nt ( s(t gr\nd 9 ! surface increas$1 ! sy/em ( timb]+ 0 gradually *ang$ to "o ( #b-;94 pol+-bo>ds4 ,^! re/$ on top ( ! %ield & 7 support$ by v]tical brea/-bo>ds :i* 9 turn 7 held by #f-;94 by #f-;94 wal+s1 brac$ ?r\gh ! upp] doors to ! iron l9+ & f ! slid+ plat=ms ( ! %ield4 ,s& & ,gravel4--,s& & gravel 7 only met at ,weehawk51 :]e two diff]5t me?ods 7 us$4 ,! fir/ me?od 0 employ$ :5 ! ro( ( ! excavation 0 ?r\gh s&4 ,x consi/$ ( excavat+ ! gr\nd #b ft4 #f ins4 ahead ( ! cutt+-edge1 ! ro( be+ held 9 place by longitud9al pol+-bo>ds4 ,^! bo>ds re/$ on ! outside ( ! sk9 at _! back end1 & at ! =w>d end on v]tical brea/-bo>ds1 brac$ f ! slid+ plat=ms & ?r\gh ! %ield doors to cross timb]s 9 ! tunnel4 ,! second me?od ( timb]+ 0 us$ 9 ! pres5ce ( gravel at ! upp] "p ( ! excavation4 ,9 su* a case1 ! excavation 0 only c>ri$ #a ft4 #c ins4 7half a %ove7 ahead ( ! cutt+-edge1 ! ro( be+ support$ by transv]se bo>ds held by pipes :i* re/$ 9 holes left 9 ! %ield4 ,aft] a small section ( ! gr\nd _h be5 excavat$ a bo>d support$ by a pipe t 0 ins]t$ und]nea? & w$g$ to x 0 plac$ aga9/ ! gr\nd4 ,^! pol+s 7 kept bel[ ! level ( ! hood1 s t :5 ! %ield 0 %ov$1 !y w\ld come inside ( x2 9 addition !y 7 brac$ ) v]tical po/s f ! slid+ plat=m4 ,! upp] "p ( ! face 0 held by longitud9al brea/-bo>ds brac$ f ! slid+ plat=m by v]tical pieces4 ,! l[] "p ( ! face 0 support$ by v]tical %eet$ pol+1 brac$ to ! tunnel ?r\gh ! l[] doors4 ,/raw & clay 7 us$ 9 front ( ! bo>ds to prev5t ! escape ( air :i* 0 v l>ge1 :5 ! tunnel 0 excavat$ ?r\gh s& & gravel4 ,! av]age rate ( progress 9 ^! mat]ials 0 #e4a ft4 p] day4 ,silt4--,:5 silt 0 enc\nt]$1 ! %ield 0 %ov$ into ! gr\nd )\t any excavation be+ done by h& ahead ( ! diaphragm4 ,z ! %ield advanc$ ! silt 0 =c$ ?r\gh ! doors into ! tunnel4 ,=c+ ! %ield ?r\gh ! silt result$ 9 rais+ ! b$ ( ! riv]1 ! am\nt t ! b$ 0 rais$ dep5d+ on ! quantity ( mat]ial br\ght into ! %ield4 ,:5 ! :ole volume ( ! excavation 0 br\ght 91 ! surface ( ! b$ 0 n affect$2 :5 ab\t #ej 0 tak5 91 ! surface 0 rais$ ab\t #c ft42 if ! %ield 0 driv5 bl9d1 ! b$ 0 rais$ ab\t #g ft4 ,:5 ! %ield 0 driv5 bl9d1 ! tunnel began to rise = ab\t #b ins41 & ! iron l9+ 0 di/ort$1 ! v]tical diamet] increas+ & ! horizontal "o decreas+ by ab\t #a ins4 ,x 0 f\nd1 h[ev]1 t ! tunnel 0 n affect$ :5 "p ( ! excavation 0 tak51 b if all ( x 0 tak5 9 or ! %ield 0 %ov$ ) op5 doors1 ! tunnel 0 l[]$4 ,a p[]ful aid 0 ?us f\nd = ! guidance ( ! %ield2 =1 if high1 ! %ield c\ld be br\ght d[n by increas+ ! quantity ( muck tak5 91 if l[1 by decreas+ x4 ,! junction ( ! %ields "u ! riv] 0 made z foll[s3 ,:5 ! two %ields ( "o tunnel1 :i* _h be5 driv5 f opposite sides ( ! riv]1 approa*$ )9 #aj ft4 ( ea* o!r1 !y 7 /opp$2 a #aj-;94 pipe 0 driv5 betwe5 !m1 & a f9al *eck ( l9es & levels 0 made ?r\gh ! pipe4 ,"o %ield 0 !n />t$ up ) all doors clos$1 :ile ! doors ( ! /ation>y %ield 7 op5$ = ! muck driv5 ahead by ! mov+ %ield4 ,?is 0 cont9u$ until ! cutt+-edges came toge!r4 ,all doors 9 bo? %ields 7 !n op5$ & ! %ield muck$ out4 ,! cutt+-edges 7 tak5 (f & ! %ields mov$ toge!r aga91 edge ( sk9 to edge ( sk94 ,z ! sections ( ! cutt+-edges 7 tak5 (f1 ! space betwe5 ! sk9 edges 0 pol$ ) #c-;94 /uff4 ,:5 ev]y?+ except ! sk9 _h be5 remov$1 iron l9+ 0 built up inside ! sk9s2 ! gap at ! junction 0 fill$ ) concrete & long bolts 7 us$ f r+ to r+ on ! circumf]5tial jo9t4 ,l9+4--,! tunnels 7 l9$ ) ca/-iron circul> r+s ( ! segm5tal bolt$ type4 ,9 "s special cases1 ca/ /eel 0 us$ in/ead ( ca/ iron4 ,! r+s 7 made #cj ins4 long1 ) an int]nal diamet] ( #ba ft4 #b ins4 & an ext]nal "o ( #bc ft4 ,! r+s 7 compos$ ( n9e equal segm5ts ( #gg ins4 ext]nal circumf]5tial l5g? ea*1 except ! two segm5ts adjo9+ ! key :i* 7 equal to ! o!r segm5ts ) ! diff]5ce1 t "o end jo9t 0 n radial b =m$ s z to make an op5+ #ab4be ins4 wide at ! outside & #ab4fj ins4 at ! inside1 :i* 0 clos$ by ! key segm5t4 ,ea* segm5t _h six bolts 9 ! circumf]5tial jo9t1 ! key _h "o1 s t !re 7 #fg bolts 9 "o circumf]5tial jo9t4 ,ea* ( ! twelve longitud9al or radial jo9ts _h five bolts1 9 all #abg bolts p] r+4 ,! circumf]5tial flanges ( ea* plate 7 /r5g!n$ by two transv]se webs or fea!rs on ea* flange4 ,ea* segm5t 0 provid$ ) a #a 94 gr\t hole clos$ ) a screw plug4 ,9 ord] to pass ar\nd curves1 :e!r horizontal or v]tical1 or to correct deviation f ! l9e or grade1 tap]+ 0 us$2 by ?is is meant ! plac+ ( r+s 9 ! tunnels :i* 7 wid] ?an ! /&>d r+s1 ei!r at "o side 7horizontal tap]s or l9]s71 or at ! top 7depressors71 or at ! bottom 7elevators74 ,tap]s 1 or ev5 #a 94 7 us$4 ,! tap] r+s 7 made by ca/+ a r+ ) "o circumf]5tial flange mu* ?ick] ?an usual & !n ma*9+ x (f to ! tap]4 ,gr\t+4--,f ! ext]ior ( ! tunnel already l9$ ) ca/-iron r+s1 gr\t 0 =c$ ?r\gh ! holes clos$ by screw-plugs1 at a pressure ( #ij lbs4 p] sq4 94 ,! gr\t 0 compos$ ( #a ,portl& cem5t & #a s& by volume & 0 =c$ 9 by a specially con/ruct$ ma*9e1 s x =m$ a %ell ( cem5t ne>ly #c ins4 ?ick ar\nd ! ext]ior ( ! iron l9+4 ,! gr\t+ began at ! l[] segm5t2 ! cem5t 0 =c$ 9 until x rea*$ ! hole above1 !n ! hole 0 plugg$1 & ! gr\t+ 0 c>ri$ on f ! consecutive hole & s on until all ! tunnel 0 f9ally encas$ 9 gr\t1 z x fill$ e crevice betwe5 ! outside ( ! l9+ & ! gr\nd z excavat$4 ,! ca/-iron r+s ( ! tunnel 7 cov]$ ) a concrete l9+ :i* 0 plac$ 9 ! foll[+ ord]3 ,fir/1 on ! inv]t2 second1 on ! duct b5*es2 ?ird1 on ! ar*2 f\r?1 on ! ducts2 fif?1 on ! face ( ! b5*4 ,be=e any concrete 0 plac$1 ! surface ( ! iron 0 clean$ by scrap]s & wire bru%es & by wa%+ x ) wat]4 ,! inv]t 0 built 9 sections #cj ft4 long & ! duct b5*es 7 con/ruct$ soon aft]4 ,^! duct b5*es 7 built ) sev]al /eps = ! ducts to be laid lat]4 ,!y 7 built by means ( a travel+ /age on :eels :i* ran on tracks on ! work+ plat=m ( ! tunnel4 ,! ar* 0 con/ruct$ soon aft]4 ,fir/ ! portion f ! duct b5*es to ! haun*es1 !n ! ar* prop]1 0 built on travel+ c5t]s on tracks laid on ! /eps ( ! duct b5*es4 ,! concrete 0 receiv$ 9 -cu4-yd4 dump+ buckets1 f ! flat c>s on :i* !y 7 run2 ! buckets 7 hoi/$ to ! level ( ! l[] plat=m ( ! ar* by a small ,lidg]wood compress$ air hoi/]4 ,at ?is level ! concrete 0 dump$ on a travel+ c> or /age & mov$ 9 t to ! po9t on ! =m :]e x 0 to be plac$4 ,= ! l[] "p ( ! ar* ! concrete 0 ?r[n directly into ! =m f ?is travel+ "p ( ! /age4 ,fig4 #adj %[s ! cross-section ( ! tunnel ) ! iron l9+ & concrete4 ,illu/ration3 ,section 9 ,s& & ,gravel or ,rock ,section 9 ,hudson ,riv] ,silt1 ) f\ndations ,,fig4 #adj4--,typical ,cross-,sections ( ,"o ,tube ( ,p5nsylvania ,railroad ,tunnel ,"u ! ,hudson ,riv]4 ,haul+4--,a work+ plat=m1 made up ( #e-;ft4 sections1 0 built inside ! tunnel & kept close to ! %ield4 ,on ?is plat=m two l9es ( indu/rial railway tracks ) swit*es & sid+s at ! locks1 & a head+1 7 laid = haul+ mat]ials & spoils4 ,^! l9es conv]g$ into a s+le track 9 pass+ ?r\gh ! air locks4 ,at ! %aft elevators1 !y t]m9at$ 9 a /eel plate floor to avoid swit*es4 ,betwe5 ! locks ( ! bulkheads 0 in/all$ an electrically driv5 cable sy/em1 to haul ! load$ muck up grade & to empty ! flat c>s4 ,f ! fir/ bulkhead to ! %aft1 ! c>s 7 haul$ up grade by a /eam haul+ eng9e4 ,at ! ,manhattan end !re 0 "o #aj-;,h4,p4 eng9e = ea* tunnel1 :ile at ,weehawk5 "o #be-;,h4,p4 eng9e s]v$ = bo? tunnels4 ,ea* %aft conta9$ two elevators driv5 by a d\ble-cable1 rev]sible s+le-drum /eam-hoi/+ eng9e4 ,a gr\ty frame 0 built ov] ! %afts1 & on ! plat=ms ov] ?is frame 7 n>r[-gauge tracks1 ext5d+ f ! elevators to ! muck-*utes & to po9ts :]e ! l9+ segm5ts 7 load$ on ! c>s4 ,! elevators 7 arrang$ to /op at bo? ! gr\nd & ! gr\ty plat=m levels4 ,! roll+-/ock at ea* ( ! tunnels consi/$ ( #ge flat c>s = mov+ ! tunnel segm5ts1 & ( ab\t #ej muck c>s1 ea* ( #a cu4 yd4 capacity4 ,plant4--,! plants locat$ at ea* end ( ! tunnel ne> ! %afts 7 almo/ id5tical4 ,ea* consi/$ ( ?ree #ejj-;,h4,p4 ,/irtl+ boil]s1 :i* suppli$ /eam at #aej lbs4 pressure4 ,fe$ wat] 0 suppli$ by ?ree #ac metropolitan injectors1 & two ,blake duplex pumps4 ,two ,wor?+ton surface cond5s]s1 ea* ( #bbej sq4 ft4 cond5s+ surface1 took c>e ( ! exhau/ f ! eng9es & compressors4 ,cond5s+ wat] 0 pump$ f ! riv] ?r\gh a #af-;94 pipe4 ,! high-pressure air 0 suppli$ by a duplex ,+]soll-,s]geant compressor1 ) cross-comp\nd /eam end #ad #bf #cj ins4 & simple wat]-jacket air cyl9d]s #ac #cf ins4 ,its capacity at #ajj r4p4m4 0 #ajhe cu4 ft4 free air p] m9ute4 ,! maximum pressure 0 #acj lbs4 p] sq4 94 ,! air = ! pneumatic work+ 0 suppli$ by ?ree #ad #bf #cj 94 duplex ,+]soll-,s]geant compressors4 ,! maximum capacity ( ! ?ree 0 #ab1jjj cu4 ft4 free air p] m9ute at #abe r4p4m4 & a dis*>ge pressure ( #ej lbs4 p] sq4 94 ,! suction air 0 tak5 f ! outside ab\t #aj ft4 above ! ro( ( ! eng9e h\se4 ,?ree aft]cool]s1 #cb ins4 #aa ft4 #d ins41 ea* hav+ #hji sq4 ft4 cool+ surface ( t9n$ brass tubes1 cool$ ! l[-pressure dis*>ge to )9 #aj ,f4 ( ! temp]ature ( ! cool+-wat]4 ,f ! aft]cool]s1 ! air pass$ into ?ree /eel receiv]s ea* #ed #ab ft41 plac$ outside ! eng9e room & fitt$ ) weigh+ safety valves4 ,! receiv]s 7 connect$ to two #aj-;94 ma9s2 "o s]v+ ! nor?1 ! o!r ! s\? tunnel4 ,a f\r? receiv] ( ! same size 0 built to receive ! dis*>ge ( ! high-pressure compressor1 ?r\gh a #d-;94 pipe4 ,! high-pressure wat] requir$ = ! %ield 0 furni%$ by ?ree ,blake direct-act+1 duplex pumps ) outside pack$ plung]s4 ,! /eam end 0 #af #ah ins41 ! wat] end #b #ah ins4 ,at #ee r4p4m4 pump+ aga9/ #ejjj lbs4 p] sq4 941 ! capacity ( ea* pump 0 #eg gals4 p] m9ute4 ,two ( !m1 "o on ea* tunnel1 7 suffici5t to run ! %ields & ! ?ird 0 held 9 res]ve4 ,! high-pressure wat] 0 convey$ to ! front by means ( a #b-;94 d\ble1 extra /rong pipe :i* 0 buri$ betwe5 ! eng9e room & ! %aft1 9 a tr5*1 to prev5t freez+ 9 cold wea!r4 ,! electric curr5t = light & p[] 0 suppli$ by two #ajj-,k4,w4 #bej-volt ,g4,e4 direct-curr5t g5]ators directly connect$ to ,ball ,wood high-spe$ eng9es runn+ at #bej r4p4m4 ,! swit*bo>d _h two ma*9e panels1 two di/ribut+ panels & "o panel c>ry+ a circuit break] = ! traction circuit4 ,illum9ation4--,! tunnel 0 light$ by electricity1 !re be+ two r[s ( lamps1 "o 9 ! cr[n & "o 9 ! s\? axial f9e4 ,! lamps 7 #af-;c4p41 #bdj-volt1 two-wire sy/em1 & 7 spac$ #ce ft4 ap>t 9 ! cr[n & #ab ft4 ap>t on ! axial l9e4 ,9 addition1 five ne/s ( #e lamps ea* 7 us$ at ! front4 ,c&les 7 suppli$ = miscellane\s & em]g5cy uses4 ,! sockets = electric globes 7 fitt$ to a wood5 reflector1 coat$ ) :ite enamel pa9t on ! inside4 ,,*apt] ,,xxi4 ,,subm>9e ,,tunnel+ 7,cont9u$72 ,,tunnels ,,at ,,v ,,%all[ ,,dep?4 ,,! ,,c(f]dam ,,me?od4 ,,! ,,pneumatic ,,caisson ,,me?od4 ,,! ,,jo9+ ,,toge!r ,,sections ,,( ,,tunnels ,,built ,,on ,,l&4 ,! tunnels on ! riv] b$ or at su* a %all[ dep? t only a few feet ( mat]ial w rema9 betwe5 ! bottom ( ! riv] & ! ro( ( ! tunnel c be built 9 ?ree diff]5t ways1 viz41 7#a7 by a c(f]dam2 7#b7 by pneumatic caissons2 7#c7 by s9k+ & jo9+ toge!r :ole sections ( tunnels t 7 built on l&4 ,! ,c(f]dam ,me?od4--,! ,van ,bur5 ,/reet ,tunnel1 ,*icago ,riv]4--,accord+ to ! c(f]dam me?od1 ! "w is attack$ at "o ( ! %ores1 & ! tunnel built 9 sections ( su* l5g? z n to int]f]e ) ! fl[ ( wat] or ! navigation ( ! riv]4 ,r\nd ! entire ext]ior l9e ( ! fir/ section a d\ble-wall$ c(f]dam is built1 & /rongly brac$ transv]sely1 s z to )/& ! pressure ( ! wat]4 ,:5 ! wat] is pump$ out1 a s+le-wall$ c(f]dam is built )9 ! fir/1 leav+ suffici5t di/ance betwe5 ! two to all[ ( ! con/ruction ( ! masonry4 ,! soil is !n remov$ )9 ! inn] c(f]dam1 & ! tunnel con/ruct$ f ! f\ndation4 ,:5 ! end ( ! tunnel rea*es ! *annel end ( ! c(f]dam1 a crib-wall is erect$ ov] ! end ( ! complet$ tunnel4 ,?is crib1 9 turn1 =ms ! end wall ( ano!r c(f]dam1 built 9 cont9uation ( ! fir/1 s z to all[ ! second section to be proce$$ )1 & at ! same "t to facilitate ! removal ( ! c(f]dams ( ! fir/ section4 ,! "w goes on cont9u\sly 9 ?is way until ! di/ant %ore is rea*$4 ,,van ,,bur5 ,,/reet ,,tunnel1 ,,*icago4 ,! ,van ,bur5 ,/reet tunnel1 built to c>ry a d\ble-track /reet railway "u ! ,*icago ,riv]1 0 complet$ 9 #ahid by ! c(f]dam me?od4 ,! special features ( ! tunnel#ad are3 7#a7 ! unusually l>ge dim5sions ( ! cross-section ( #cj ft4 #ae ft4 #i ins42 7#b7 its con/ruction inside ( c(f]dams ( great l5g? & wid?2 7#c7 ! con/ruction "u "s v high build+s call+ = great c>e & v /rong tempor>y & p]man5t supports4 #ad 8,eng4 ,news10 ,april #ab1 #ahib4 ,! special feature ( ! "w = our pres5t purpose 0 ! con/ruction ( ! tunnel across ! riv]4 ,to accompli% ?is a c(f]dam 0 built out f ! we/ %ore ( ! riv] to its middle1 & ! tunnel con/ruct$ )9 x l ! build+ ( any o!r /ructure )9 a c(f]dam4 ,transv]se & longitud9al sections ( ?is c(f]dam are %[n by ,fig4 #ada4 ,z w be se51 x 0 a simple d\ble-wall c(f]dam1 ) a cle> wid? betwe5 ! walls ( #eh ft41 & brac$ transv]sely z %[n4 ,inside ( ?is a s+le-wall c(f]dam ( piles 0 con/ruct$1 ) a cle> wid? j suffici5t to all[ ! con/ruction ( ! masonry )9 x4 ,:5 ! tunnel end rea*$ ! *annel end ( ! c(f]dam1 a crib-wall 0 built ov] ! end ( ! complet$ tunnel1 z %[n by ! draw+s4 ,?is crib-wall 0 int5d$ to =m ! end wall ( ano!r c(f]dam1 :i* 0 built out f ! ea/ %ore1 & )9 :i* ! rema9+ half ( ! tunnel 0 built z ! fir/ half _h be54 ,! draw+s %[ ! "* ( ! tunnel masonry & ( ! c5t]+ ^u :i* x 0 built4 ,illu/ration3 ,,transv]se ,,section ,,( ,,c(f]dam ,,& ,,tunnel ,,section ,,%[+ ,,me?od ,,( ,,con/ruct+ ,,crib ,,dam4 ,,fig4 #ada4--,sections ( ,c(f]dam1 ,van ,bur5 ,/4 ,tunnel1 ,*icago4 ,! ,van ,bur5 ,/reet tunnel 0 ! la/ ( ! ?ree tunnels "u ! ,*icago ,riv]1 con/ruct$ accord+ to ! c(f]dam me?od4 ,at ! "t ! tunnels 7 con/ruct$ ! b$ ( ! riv] 0 #ag ft4 deep4 ,9 connection ) ! h>bor & riv] improvem5ts1 ! ,f$]al ,gov]nm5t ord]$ ! ,*icago ,riv] to be l[]$ s z to give a dep? ( #bf ft4 ( wat]4 ,?is necessitat$ ! l[]+ ( ! tunnel ro( & ! excavation = a deep] floor :i* 0 a v difficult op]ation4 ,?is "w 0 describ$ 9 8,eng4 ,news10 ,sept41 #aijf4 ,,! ,,pneumatic ,,caisson ,,me?od4--,,! ,,tunnel ,,"u ,,! ,,h>lem ,,riv]4 ,9 ! e>ly sev5ties ,pr(4 ,w9kl] propos$ to con/ruct a tunnel "u ! ,riv] ,danube to connect ! v>i\s portions ( ! ,vi5na1 ,au/ria1 und]gr\nd railway1 & to use caissons 9 ! con/ruction4 ,pr(4 ,w9kl] propos$ to build caissons f #cj ft4 to #de ft4 long1 ) a wid? dep5d+ ^u ! lat]al dim5sions adopt$ = ! tunnel masonry4 ,! caisson 0 to be made ( metal plates & angle iron ) rivet$ connections on all sides except ^? runn+ v]tically transv]se to ! tunnel axis1 ^: connections 7 to be bolt$4 ,9 ! middle ( ! ro( an op5+ 0 to be left2 ?is 0 = ! %aft hav+ ! air-locks to all[ ! passage ( m51 mat]ials1 & compress$ air4 ,across ! riv] two p>allel r[s ( piles 7 to be driv5 into ! riv] b$1 to fix ! place :]e ! caisson 0 to be sunk4 ,!n ! fir/ caisson ne> ! %ore 0 to be l[]$ 9 ! ord9>y way1 & a second caisson 0 to be imm$iately sunk v close to ! fir/ "o4 ,:5 bo? caissons _h rea*$ ! plane ( ! tunnel floor1 ! sides :i* 7 9 contact 7 to be unbolt$ & remov$1 & ! small space betwe5 made wat]-tight4 ,! *amb]s ( ! two caissons 7 to be op5$ into a s+le l>ge "o communicat+ above by means ( two %afts4 ,at ! same "t t ! masonry 0 be+ built 9 ! fir/ two caissons1 f ! inv]t$ ar* up1 a ?ird caisson 0 to be sunk2 & :5 by excavation x _h rea*$ ! plane ( ! project$ tunnel floor1 ! p>titions 7 to be remov$ s t ! ?ree caissons 7 9 communication1 =m+ a l>ge s+le caisson4 ,!n ! out] p>tition ( ! fir/ caisson 0 to be remov$1 & ! masonry ( ! subm>9e tunnel connect$ ) ! portion ( ! tunnel built on l&4 ,9 a simil> mann] all ! caissons 7 to be sunk2 & :5 ! la/ "o 0 plac$1 & ! masonry l9+ con/ruct$1 & connect$ ) ! portion ( ! tunnel built on ! o!r %ore ( ! riv]1 ! p>tition walls 7 to be batt]$ d[n1 & ! subm>9e tunnel completely con/ruct$ & op5 to traffic4 ,! ,h>lem ,riv] ,tunnel4--,! pneumatic caissons me?od 0 employ$ 9 ! con/ruction ( ! tunnel "u ! ,h>lem ,riv] = ! ,new ,york ,rapid ,transit ,railway4 ,! tunnel prop] consi/$ ( two p>allel tubes rivet$ to ea* o!r & surr\nd$ by a cradle ( concrete z %[n 9 ,fig4 #aba1 page #baf4 ,! tunnel 0 built 9 ?ree sections3--,! fir/1 f ! ,manhattan %ore well t[>ds ! middle ( ! riv]2 ! second1 f ! %ore ( ! ,bronx t[>ds ! middle ( ! riv]2 & ! la/1 ! section unit+ ! o!r two & complet+ ! tunnel4 ,ea* section 0 built )9 a specially con/ruct$ work+-*amb]1 consi/+ ( timb] side walls =m+ a wood5 caisson1 s con/ruct$ t compress$ air c\ld be us$4 ,?is work+-*amb] ( ,mr4 ,mc,bean pres5t$ "s novel features1 inasmu* z ! caisson 0 n built on l&1 b "u wat]4 ,9 build+ ! tunnel1 ! ,h>lem ,riv] 0 dr$g$ to a c]ta9 dep?1 s z to leave only #f ft4 or #h ft4 ( excavation to be done be=e rea*+ ! l9e ( sub-grade ( ! propos$ /ructure4 ,two s]vice plat=ms 7 built on piles #aj ft4 ap>t longitud9ally1 & cut (f at a po9t above mean high-wat] m>k1 brac$ 9 ! usual mann]1 & cov]$ ) heavy planks1 to s]ve z ! floor ( ! plat=m4 ,on ?is plat=m 7 plac$ rails = ! tra9s us$ 9 ! transportation ( mat]ials4 ,^! plat=ms 7 also us$ 9 ma9ta9+ ! p]fect alignm5t ( ! caissons4 ,)9 ! plat=ms & along ! dr$g$ *annel f\r longitud9al r[s ( piles 7 sunk4 ,^! piles 7 accurately br\ght to l9e by beams bolt$ toge!r1 & plac$ across & above ! wat]-level4 ,a few beams 7 also add$ = ! purpose ( brac+ ! piles transv]sely1 aft] :i* !y 7 cut (f "u wat] & capp$4 ,illu/ration3 ,,fig4 #adb4--,%[+ ,work+ ,plat=ms & ,piles ,sunk 9 ! ,dr$g$ ,*annel4 ,fig4 #adb %[s ! mann] 9 :i* ! work+ plat=ms 7 con/ruct$1 & also ! r[s ( piles sunk 9 ! dr$g$ *annel4 ,betwe5 ! piles a v /rong frame 0 plac$1 made up ( wal+ pieces & two transv]se beams #ad ins4 by #ad ins4 ea*1 plac$ "o bel[ ! o!r at a di/ance ( #e ft4 #h ins41 & /rongly brac$ toge!r4 ,guid+-beams 7 fix$ on ea* side ( ! frame = ! %eet+ piles4 ,! frames 7 built 9 sections ( diff]5t l5g?s1 & plac$ directly above ! cap-pieces ( ! pile-b5ts sunk 9 ! dr$g$ *annel4 ,! longitud9al sides ( ! caisson 7 con/ruct$ by s9k+ two r[s ( %eet+ piles1 ea* r[ be+ close to a s]vice plat=m4 ,! %eet+ piles 7 made up ( yell[-p9e timb]s #ab ins4 by #ab ins42 ?ree piles bolt$ toge!r =m$ a section #c ft4 wide4 ,ea* section 0 groov$ & tongu$1 s z to be firmly connect$ ) ! adjac5t sections to be sunk4 ,! l[] ends ( ! piles 7 cut w$ge-%ap$1 ) a %>p edge to (f] a small resi/ance :ile p5etrat+ ! soil4 ,! %eet+-piles 7 !n cut (f "u wat]1 :i* op]ation 0 successfully c>ri$ out by means ( a circul> saw op]at$ by a pile-driv+ ma*9e4 ,! %eet+ 0 also ext5d$ betwe5 two plat=ms to make a bulkhead1 & 9 ?is way ! f\r sides ( ! caisson 7 built up4 ,p>ticul> att5tion 0 always giv5 to ! alignm5t ( ! %eet+ piles1 :i* 0 obta9$ by guid+ ! piles ) ! timb]s plac$ longitud9ally1 "o bel[ ! wat]-l9e 9 connection ) ! frames locat$ betwe5 ! pile-b5ts1 & ! second along ! inn] edge ( ! s]vice plat=m1 z %[n 9 ,fig4 #adc4 ,illu/ration3 ,,fig4 #adc4--,%[+ ,%eet+-,piles = ! ,sides ( ! ,caisson & ,truss$ ,beam = ! ,ro(4 ,! caisson 0 complet$ by plac+ a ro( cov]+ ! sides4 ,?is ro( 0 #dj ins4 ?ick1 made up ( ?ree lay]s ( #ab-;94 beams plac$ transv]sely to ! axis ( ! caisson1 :ile betwe5 ! beams planks #b ins4 ?ick 7 plac$ l5g?wise & bolt$ toge!r1 s z to make a firm1 solid /ructure4 ,! ro( 0 built a%ore1 9 sections ea* v>y+ f #ci ft4 to #acj ft4 long4 ,! edges ( ! ro( fitt$ ! sides ( ! caisson p]fectly2 & :5 ea* section 0 t[$ to ! prop] spot1 x 0 sunk & made secure4 ,"u ! ro( 7 plac$ six longitud9al beams1 #ab ins4 by #ad ins41 call$ 8rang]s10 re/+ on ! cap-pieces ( ! pile-b5ts t 7 laid across ! space ( ! propos$ tunnel2 :ile ! extreme rang]s 7 us$ = ! purpose ( fitt+ above ! %eet+-piles ( ! caisson1 9 ord] to make ! latt] wat]-tight4 ,! two extreme rang]s 7 provid$ ) ,t-irons1 ! flat side be+ laid on ! %eet+-piles1 :ile ! web p5etrat$ ! rang] by reason ( ! weight ( ! load re/+ on ! ro(1 = ! purpose ( s9k+ x to ! requir$ po9t4 ,e>? 0 next heap$ on ! ro(1 & 9 ?is way a l>ge work+-*amb] 0 prep>$1 z %[n 9 ,fig4 #add4 ,illu/ration3 ,,fig4 #add4--,%[+ ! ,caisson ) ! ,work+-,*amb]4 ,! work+-*amb] built on ! ,manhattan side ( ! ,h>lem ,riv] 0 #baf ft4 long1 provid$ ) two rectangul> %afts #g ft4 by #ag ft41 r5d]$ wat]-tight1 & ris+ above ! high-wat] m>k ( ! riv]4 ,)9 ^! %afts ! air-locks ( ! tunnel tubes 7 plac$1 s t ! "w c\ld be c>ri$ on by means ( compress$ air4 ,! pressure ( ! air 0 us$ to expel ! wat]1 be+ suffici5tly int5se to equilibrate a column ( wat] equal to ! dep? ( ! l[e/ po9t ( ! ro( ( ! caisson4 ,:5 ! work+-*amb] 0 con/ruct$1 ! tunnel prop] 0 begun by excavat+ ! soil d[n to ! requir$ level2 ! concrete 0 !n laid on4 ,x 0 j at ?is po9t1 :5 a l>ge "p ( ! ro( 0 con/ruct$ & support$ only by ! %eet+-piles ( ! sides ( ! caisson1 t ! writ] ( ?is article fe>$ t ?is novel me?od ( tunnel+ w\ld prove a failure4 ,! t5d5cy ( ! timb] to float1 aid$ z x 0 by ! air pressure )9 ! caisson1 0 c\nt]act$ only by ! weight ( ! e>? heap$ on ! ro(1 & by ! friction ( ! soil aga9/ ! feet ( ! %eet+-piles4 ,?is friction 0 only a small quantity1 z ! soil 0 loose1 s t x 0 consid]$ r risky & dang]\s to place reliance on su* a feeble quantity4 ,?is fe> 01 un=tunately1 ju/ifi$ on two occasions1 :5 on cutt+ (f a portion ( ! pile-b5ts "s ( ! %eet+-piles got loose & wat] flood$ ! :ole *amb]1 b1 happily1 )\t loss ( life4 ,z ! *amb] 0 "o ( l>ge dim5sions1 ! workm5 _h "t en\gh to effect _! escape4 ,x may be rem>k$ t dur+ ^! tr\bles only a few ( ! %eet+-piles 7 displac$1 :ile ! caisson itself (f]$ a /\t & successful resi/ance1 due to its be+ /rongly brac$ transv]sely4 ,! accid5ts 71 !re=e1 limit$ to a few piles1 in/ead ( affect+ ! entire caisson4 ,on ! occasion ( ! fir/1 ! repairs 7 effect$ by s9k+ ! piles to a great] dep?1 cont9u+ d[n until rock 0 enc\nt]$4 ,aft] t1 ! wat] 0 pump$ out & ! "w resum$4 ,9 repair+ ! second accid5t1 ! %eet+-piles 7 driv5 d[n to b$-rock1 & ! surr\nd+ soil /r5g!n$ by cem5t =c$ ?r\gh ! loose soil ar\nd ! piles4 ,?is rem$y prov$ effective1 & no fur!r tr\ble occurr$ to delay ! "w on ! ,manhattan side ( ! ,h>lem ,riv]4 ,illu/ration3 ,,fig4 #ade4--,%[+ ! ,tunnel ,con/ruct$ )9 ! ,caisson4 ,on ! concrete b$ ( ! tunnel ! segm5ts ( ! metal l9+ 7 plac$ & surr\nd$ by concrete1 z requir$ by ! plans & specifications 7,fig4 #ade74 ,! contractors _h plann$ to unbolt ! ro( f its hold+s1 to remove by means ( dr$g]s ! e>? :i* _h be5 heap$ on x1 & ?us set ! ro( afloat1 aft] :i* x 0 to be t[$ )9 ! two work+ plat=ms already erect$ on ! ,bronx %ore4 ,b ,mr4 ,mc,bean devis$ a simpl] & m economic1 b at ! same "t m dang]\s1 way ( con/ruct+ ?is second section ( ! tunnel4 ,he ?\ght t ! upp] half ( ! tunnel prop] c\ld be us$ in/ead ( ! timb] ro(1 !reby r$uc+ ! capacity ( ! work+ *amb]1 & limit+ ! use ( compress$ air4 ,9 ?is way he disp5s$ ) ! removal ( timb]1 & also ( ! e>? heap$ on ! ro(4 ,9 build+ ?is ,bronx section1 a *annel 0 dr$g$ along ! l9e ( ! tunnel to a dep? ( #e ft4 f ! f\ndation-b$ ( ! propos$ tunnel4 ,! work+ plat=ms 7 con/ruct$ on bo? sides ( ?is *annel1 q simil> to ^? erect$ on ! o!r half ( ! tunnel2 & betwe5 !m pile-b5ts 7 sunk1 capp$ ) #ab-;94 by #ab-;94 beams4 ,ov] ! cap-pieces rang]s 7 plac$ longitud9ally1 :i* also re/$ on ! sides ( ! wood5 work+ caisson1 ,fig4 #adf4 ,! %eet+-piles 7 cut (f at level1 b mu* l[] d[n ?an 9 ! fir/ half ( ! tunnel4 ,! ro( 0 built on floats made ( #ab-;94 by #ab-;94 timb] laid transv]sely #d ft4 ap>t & support+ a floor ( #c-;94 by #ab-;94 planks r5d]$ wat]-tight4 ,! sides ( ! floats 7 made by v]ticals1 #d ins4 by #f ins41 & planks1 #c ins4 by #ab ins41 c>efully caulk$4 ,a tempor>y floor 0 built on ! base ( ! float1 consi/+ ( transv]se beams1 #af ins4 by #af ins41 plac$ #h ft4 ap>t4 ,a c5t] piece1 #aj ins4 by #af ins41 0 laid s z to correspond ) ! axis ( ! tunnel2 & on ea* side ( x1 o!r p>allel beams1 #af ins4 by #af ins41 correspond+ to ea* c5t] ( ! circul> metal l9+ ( ! tunnel2 ! beams1 longitud9al & transv]sal1 7 /rongly bolt$ toge!r4 ,! tempor>y floor 0 complet$ by bo>d+ ! spaces left betwe5 ! v>i\s beams4 ,illu/ration3 ,,fig4 #adf4--,%[+ ,sides ( ! ,caisson & ,supports = ! ,ro(4 ,on ?is float1 ! upp] half ( ! tunnel 0 con/ruct$ by erect+ ! segm5ts ( ! metal l9+1 :i* 7 /rongly support$1 s z to prev5t any settl+ or di/ortion2 ! concrete 0 !n built up 9 a l>ge flange ) v]tical susp5sion rods1 f\r to ea* b>4 ,! r+s ( ! tunnel 7 #f ft4 ea*1 ! weight ( ea* l9+ be+ #da1jjj lbs41 ! concrete cov]+ #fah cubic feet4 ,! second "p ( ! tunnel 0 #cjj ft4 long1 ) ro( con/ruct$ 9 ?ree sections--two ( #ij ft4 9 l5g? ea* & ! ?ird ( #hd ft4 ,ea* ( ^! sections alt]nat$ ) a small] section1 #ab ft4 long1 provid$ ) air-locks4 ,! %orte/ ( ! ?ree sections 0 ! fir/ "o set up1 & 0 con/ruct$ close to ! ,bronx side ( ! ,h>lem ,riv]4 ,= ?is purpose ! two extreme ends ( ! section 7 clos$ by means ( /eel plates =m+ diaphragms1 built #f ft4 inw>d1 ?us leav+ "o r+ project+ out at ea* end4 ,op5+s 7 left on ! top ( ^! project+ r+s = access by div]s4 ,! ext]ior ( ! upp] half section ( ! p]man5t tunnel 0 fill$ ) wat] until x 0 l[]$ into position4 ,x 0 direct$ by means ( tackles atta*$ to v]tical eye-b>s1 :i* 7 /rongly fix$ to ! flanges ( ! spr++ l9e ( ! ar*1 & bolt$ to ! beams ( ! tempor>y floor4 ,9 ?is way ! ro( 0 t[$ into place1 & l[]$ by means ( /one balla/1 until x re/$ on ! cap-pieces & frames ( ! pile abutm5ts1 ! sides ( ! ro( rema9+ j on top ( ! %eet+-piles t =m$ ! sides ( ! caisson1 z %[n 9 ,fig4 #adg4 ,p]fect alignm5t 0 obta9$ by wires /rung at ea* end & along ! side ( ! ro(1 correspond+ to po9ts fix$ on ! work+ plat=ms & sight$ ) transits4 ,su* accuracy 0 obta9$ t ! circumf]5tial flanges ( ! out] #f-;ft4 r+ 7 br\ght into contact ) ^? ( ! #ab-;ft4 section already con/ruct$4 ,a div] !n ent]$ by ! op5+ left 9 ! project+ r+1 & bolt$ ?is section ( ! ro( to ! prec$+ "o4 ,by remov+ ! iron diaphragm1 ! consecutive sections 7 unit$ into "o4 ,:5 ! div] complet$ 8 "w1 ! op5+ 0 clos$ up1 & compress$ air us$ to keep ! wat] out ( ! box includ$ betwe5 ! ro( & ! tempor>y floor+4 ,illu/ration3 ,,fig4 #adg4--,%[+ ! ,ro( ( ! ,caisson ,=m$ by ! ,upp] ,half ( ! ,tunnel4 ,! rema9+ sections ( ! tunnel ro( 7 built 9 ! same way1 until ! la/ abutt$ aga9/ ! "p ( ! "w con/ruct$ )9 ! caisson "u ! high wood5 ro( on ! ,manhattan side ( ! riv]4 ,! foll[+ me?od 0 adopt$ = ! purpose ( connect+ ! few p>ts ( ! tunnel :i* _h be5 diff]5tly con/ruct$4 ,! diaphragm at ! end ( ! la/ section ( ! tunnel ro( 0 con/ruct$ s z to abut aga9/ ! la/ circumf]5tial flanges ( ! iron l9+ )\t leav+ a project+ r+4 ,x 0 cont9u$ above ! metal & concrete l9+ ( ! ro( 9 a rectangul> =m1 & ( ! same height & wid? z ! wood5 bulkhead ( ! work+-*amb] on ! ,manhattan side ( ! riv]4 ,! diaphragm 0 made ( rivet$ plates & angles1 ) an op5+ #bj ins4 by #cj ins41 bolt$ s z to be removable at w4 ,! diaphragm 0 ( ! same height z ! ro( & 0 connect$ ) a ro(-plate to ! rang]s support+ ! ?ick wood5 ro(4 ,o!r /eel plates1 plac$ v]tically1 7 rivet$ to ! diaphragm & bolt$ to ! caisson4 ,all ?is "w 0 c>ri$ on by div]s4 ,! wood5 bulkhead 0 cut to ! spr++-l9e ( ! ar*2 & betwe5 ! two p>ts ( ! tunnel1 built by diff]5t me?ods1 a bulkhead 0 plac$1 made ( /eel plates #ad ins4 long1 :i* prev5t$ ! entrance ( wat] into ! work+-*amb]4 ,illu/ration3 ,,fig4 #adh4--,%[+ ! ,tunnel ,complet$ by ,build+ ! ,l[] ,half )9 ! ,caisson4 ,:5 ! diff]5t sections 7 jo9$ toge!r1 & all ! op5+s clos$ & made wat]-tight1 cem5t-gr\t 0 p\r$ on ! ro(1 & e>? 0 heap$ up to a height ( #e ft4 ,! #cjj ft4 ( ! ro(1 re/+ on %eet+-piles & provid$ ) diaphragms at ! extreme ends1 =m$ a wat]-tight work+-*amb]1 or caisson1 communicat+ ) ! ext]ior by means ( ! %afts & air-locks4 ,! l[] portion ( ! tunnel 0 built "u air-pressure4 ,! pile-b5ts 7 fir/ cut (f at ! plane ( ! tunnel sub-grade1 aft] :i* ! f\ndation-b$ ( concrete 0 laid4 ,! l[] segm5ts ( ! iron l9+ 7 !n plac$ 9 position1 & ! /ructure made cont9u\s by build+ up ! lat]al walls1 consi/+ ( concrete 7,fig4 #adh74 ,no accid5ts occurr$ :ile build+ ! second "p ( ! tunnel4 ,! ,h>lem ,riv] tunnel 0 complet$ 9 contract "t1 al?\gh ! op5+ ( ! subway 0 delay$ by difficulties enc\nt]$ 9 tunnel+ ?r\gh rock 9 ! bor\gh ( ! ,bronx4 ,! writ] endeavor$ to obta9 in=mation reg>d+ ! exp5se p] l9e> foot1 b all 8 ef=ts 7 rew>d$ ) a g5]al assurance t x prov$ to be ! *eape/ me?od4 ,,s9k+ ,,& ,,jo9+ ,,toge!r ,,sections ,,( ,,tunnels ,,built ,,on ,,l&4 ,,! ,,se9e4 ,,! ,,detroit ,,riv] ,,tunnels4 ,9 ! ye> #ahif1 ,mr4 ,era/us ,wyman secur$ a pat5t = build+ subaque\s tunnels close to ! riv]1 by s9k+ & jo9+ toge!r small sections ( tunnels previ\sly built on l&4 ,ea* section w\ld h be5 provid$ ) a long v]tical tube = ! air-lock :5 compress$ air 0 to be admitt$ to expel ! wat] & p]mit ! con/ruction ( ! l9+ )9 ! sunk5 %ell4 ,?us ea* section ( ! tunnel w\ld h act$ z a pneumatic caisson2 be+1 h[ev]1 an improvem5t on ,pr(essor ,w9kl]'s sugge/ion inasmu* z ! caisson 0 a portion ( ! tunnel itself1 in/ead ( a simple inclosure = facilitat+ ! con/ruction ( ! %ield4 ,mr4 ,wyman propos$ to use ?is me?od 9 ! con/ruction ( a tunnel betwe5 ,s\? ,brooklyn & ,/apleton1 ,/at5 ,isl&2 a *>t] 0 grant$ him b ! tunnel 0 nev] built4 ,! ,tunnel "u ! ,se9e ,riv]4--,! caisson me?od ( build+ tunnels "u wat] 0 us$ at ,p>is1 ,france1 9 ! con/ruction ( ! ,metropolitan ,railroad "u ! ,se9e ,riv]4 ,! caissons design$ by ,mr4 ,l4 ,*agnaud 7 = a d\ble track l9e4 ,!y 7 sunk1 ends to ends1 & =m$ a portion ( ! tunnel l9+ :i* 0 envelop$ by a framework ( metal emb$d$ 9 concrete4 ,built-up frames c>ri$ a %ell ( /eel plat+ on ! sides1 f toes to spr++ l9es1 & on ! sides & ro( ( ! work+-*amb]4 ,a tempor>y plate diaphragm clos$ ! op5 ends4 ,?is con/ruction =m$ a vessel capable ( float+ ) a v light draft4 ,! me?od ( s9k+ ! caissons 0 z foll[s3 ,! caisson 0 erect$ on ! riv] bank & :5 complet$ x 0 laun*$ & t[$ into position betwe5 pile /ag+s :i* s]v$ ! d\ble purpose ( guid+ ! desc5t at ! beg9n+ ( ! s9k+ & ( =m+ a work+ plat=m4 ,! caisson :5 laun*$ &1 consequ5tly1 be=e ! ca/-iron l9+ _h be5 put 9 place )9 x1 weigh$ #bhj metric tons2 b1 beyond "s difficulty 9 tak+ x "u ! bridges 9 ! way1 ! t[+ 0 accompli%$ )\t s]i\s tr\ble4 ,illu/ration3 ,,fig4 #adi4--,transv]sal ,section ( ! ,caissons = ! ,tunnel "u ! ,se9e ,riv]4 ,previ\s to plac+ ! caisson 9 position betwe5 ! /ag+s1 ! portion ( ! riv] b$ x 0 to re/ ^u _h be5 level$ by dr$g+4 ,once 9 position1 ! fir/ "w 0 ! erect+ ( ! ca/-iron l9+ segm5ts )9 ! framework4 ,"w 0 !n begun by fill+ ! annul> space betwe5 ! l9+ & ! %ell ) concrete2 ?is additional weight gradually sunk ! caisson to ! riv] bottom4 ,! work+ %afts1 made up ( /eel cyl9d]s1 7 plac$ z ! s9k+ progress$ to ?is po9t4 ,illu/ration3 ,section ,a-,b4 ,section ,c-,d4 ,plan at ,jo9t4 ,,fig4 #aej4--,%[+ ! ,jo9+ ( ! ,caissons at ! ,pont ,mirabeau ,tunnel "u ! ,se9e ,riv]4 ,aft] ! caissons _h be5 sunk to ! requir$ place & 9 cont9uation ( "o ano!r1 a space ( ne>ly #e ft4 0 left betwe5 !m4 ,! con/ruction ( ! tunnel )9 ! bank ( e>? sep>at+ ! two caissons 0 z foll[s3 ,a c(f]dam 0 built ar\nd ?is space4 ,x 0 =m$ by two diaphragms clos+ ! ends ( ! tunnel1 & by two longitud9al walls sunk z tempor>y caissons1 "o on ea* side ( ! tunnel & inclos+ _! ends4 ,?is c(f]dam 0 cov]$ ) a metal work+-*amb] ^: l[] edges re/$ on top ( ! f\r walls ( ! c(f]dam4 ,! jo9ts 7 made tight by means ( rubb] or pack$ clay4 ,! wat] 9 ! c(f]dam 0 !n pump$ out1 ! e>? excavat$1 & ! masonry built 9 cont9uation ( ! two ends ( ! tunnel sections4 ,! subm]g$ sections ( ! tunnel :i* 7 all[$ to rema9 full ( wat] to r5d] !m m /able & to save ef=t 9 pump+ !m1 7 n[ made dry2 ! diaphragms 7 remov$ f ! ends ( ! caisson tunnels & ! "w made cont9u\s4 ,fig4 #adi %[s ! cross-section ( ! caissons4 ,at ! ,pont ,mirabeau cross+ ( ! ,se9e1 a slightly diff]5t me?od 0 us$1 describ$ 9 8,eng4 ,news10 ,may #ah1 #aiaa4 ,! caissons 7 sunk to ! requir$ l9e & grade ) an int]v5+ longitud9al space ( #ae ins4 betwe5 two adjo9+ caissons4 ,at ea* end ( ?is space1 :i* 0 fill$ ) ! riv] m>l1 0 sunk aga9/ ! edges ( ! caissons a holl[ cyl9d] #bj ins4 outside diamet]4 ,! int]ior ( ^! cyl9d]s 0 excavat$ & fill$ ) concrete1 ?us =m+ a cont9u\s wall on bo? sides ( ! two adjo9+ caissons4 ,! e>? f ! int]v5+ space 0 !n remov$ & concrete deposit$ f bottom op5+ tremies up to ! level ( ! top ( ! caisson4 ,aft] ne>ly "o mon? ! tunnel 0 ent]$ f ! %aft & an op5+ ! %ape & size ( ! tunnel section cut ?r\gh ! diaphragms ( ! #ae-;94 wall & ! concrete tunnel l9+ made cont9u\s betwe5 ! two sections4 ,fig4 #aej %[s ! me?od ( jo9+ ! caissons4 ,! ,detroit ,riv] ,tunnel4#ae--,) "s modifications :i* p]mitt$ disp5s+ ) compress$ air1 ! tunnel "u ! ,detroit ,riv] 0 built = ! ,mi*igan ,c5tral ,railroad1 connect+ ,detroit ) ,w9dsor1 ,canada4 ,! tunnel is #ffbe ft4 long2 ( ?is1 h[ev]1 only #bfbe ft4 are "u ! riv]1 :ile ! approa* on ! ,am]ican side is #bjjj ft4 long & t on ! ,canadian side1 #djjj ft4 ,! tunnel consi/s ( two p>allel circul> tubes #bc ft4 9 diamet]1 built up ( -94 /eel plate4 ,!y are plac$ #bf ft4 ap>t1 c5t] to c5t]1 & are connect$ by diaphragms at #ab-;foot int]vals4 #ae ,cond5s$ f a pap] by ,b4 ,h4 ,ryd]4 ,ea* section ( ! subaque\s tunnel is approximately #bfb ft4 long4 ,!re are t5 ( ^! sections & an elev5? a little ov] #fj ft4 long4 ,^! tubes 7 built at ! %ipy>ds ( ! ,great ,lakes ,eng9e]+ ,works at ,/4 ,clair1 ab\t #cj miles f ,detroit4 ,aft] ! assembl+ 0 complet$1 ! ends ( ea* tube 7 clos$ by tempor>y wood5 bulkheads to make !m float1 & ! outside %ea!d horizontally ) heavy timb]s bolt$ to ! diaphragms4 ,?is %ea?+ runn+ l5g?wise ( ! tube made a =m or pocket1 into :i* ! inclos+ jacket ( concrete 0 plac$4 ,! sections 7 !n laun*$ & t[$ d[n to ! tunnel site & sunk sep>ately 9 a tr5* on ! riv] bottom t _h be5 previ\sly dr$g$ to receive !m4 ,?is tr5* 0 dug to a wid? ( #ej ft4 & dep? v>y+ f #be to #ej ft4 by clam%ell buckets1 swung f a sc[1 work+ to a dep? bel[ ! wat] level ( #fj to #ij ft4 ,z a f\ndation = ! sections1 a grillage 0 con/ruct$ on ! surface & sunk 9 place 9 ! tr5* by d]ricks swung f a sc[4 ,! grillage 0 plac$ und]nea? ea* jo9t betwe5 ! sections & built up ( ,i-beams imb$d$ 9 concrete4 ,?is grillage is ! wid? ( ! tr5* & ab\t #cj ft4 long1 ) po/s project+ d[nw>d f ! f\r corn]s1 & ^! 7 seat$ into ! riv] bottom1 by means ( pile driv]s1 to ! desir$ grade4 ,!n ! elev5 sections ( ! tunnel 7 l[]$ & connect$1 "o at a "t4 ,by ! aid ( air tanks plac$ on ea* section ! movem5t 0 controll$ until ! f9al s9k+ ^u ! grillage 9 ! tr5*4 ,?is op]ation call$ into play ! greate/ eng9e]+ skill & +5uity4 ,:5 x is consid]$ t ! curr5t velocity at ! riv] b$ is ab\t #b ft4 p] second & mu* high] along ! surface1 "s idea c be ga9$ ( ! problems to be ov]come4 ,! movem5t ( ! enorm\s sections mu/ be absolutely "u control4 ,?irty-five-ton blocks ( concrete 7 sunk 9 ! riv] bottom up & d[n /ream to act z an*ors1 & ?r\gh !m cables 7 rigg$ & connect$ back to ! hoi/+ eng9es on ! d]rick sc[s4 ,^! 7 prev5t$ f mov+ by spuds at ea* corn]1 securely driv5 into ! riv] bottom at dep?s sometimes z great z #ij ft4 ,controll+ cables 7 also run f ! sections to ! tremie sc[ to pull "o /ructure close to ! adjo9+ section previ\sly sunk1 & ! div]s made ! necess>y connection4 ,fig4 #aea %[s cross-sections & plans ( ! tunnel z giv5 9 8,eng4 ,record10 ,m>* #b1 #aijg4 ,illu/ration3 ,,half ,,cross ,,section ,y-,y ,,half ,,cross ,,section ,z-,z ,,half ,,horizontal ,,section ,x-,x ,,half ,,top ,,view ,,fig4 #aea4--;,cross-,sections & ,plans ( ! ,detroit ,riv] ,tunnel4 ,/eel ma/s _h be5 previ\sly atta*$ to ea* end ( ! sections to enable ! eng9e]s on %ore to det]m9e ! alignm5t & locate ! exact position dur+ ! s9k+4 ,concrete 0 !n deposit$ 9 ! pockets1 completely surr\nd+ ! tubes1 =m+ a solid monoli?ic /ructure f end to end4 ,?is 0 done by means ( ! tremie process4 ,a #cb-;ft4 by #afj-;ft4 sc[ 0 equipp$ ) a concrete mix+ plant & ! tremie pipes1 ?ree 9 numb]1 ?r\gh :i* ! concrete 0 deposit$4 ,ea* pipe is #ab ins4 9 diamet]1 ( spiral rivet$ /eel1 #hj ft4 long4 ,^! pipes c\ld be rais$ or l[]$1 rea*+ f ! receiv+ hopp]s on ! sc[ to ! bottom ( ! tr5*4 ,:5 ! pipes 7 fill$ ) concrete & l[]$ into position1 a cont9u\s fl[ 0 ma9ta9$4 ,z fa/ z ! concrete escap$ at ! bottom end ( ! pipe x 0 repl5i%$ at ! top2 ?is process cont9u+ until ! entire space surr\nd+ ! section 0 fill$ to ! desir$ level1 & "u ! pressure produc$ n only by ! dep? ( wat] "u :i* x 0 subm]g$1 b also by ! weight ( ! long column ( concrete conta9$ 9 ! tubes4 ,x is int]e/+ to note t ?is is ! fir/ "t a l>ge am\nt ( concrete has be5 deposit$ at a dep? ( #gj ft4 by ?is me?od1 & ^u ! accompli%m5t ( ?is task 9 a measure dep5d$ ! successful build+ ( ! tunnel4 ,inside ! tubes 0 plac$ a l9+ ( re9=c$ concrete #bj ins4 ?ick4 ,side walls 7 built up f ?is r+ to provide ducts1 :i* c>ry ! electrical cables = ! di/ribution ( p[]1 light+1 signal & telegraph wires4 ,!y also s]ve to provide a footwalk along ! side ( ! tunnel4 ,!re are cross passages 9 ! tunnel e #bjj ft41 & also v>i\s ni*es = ! diff]5t equipm5t ne$$ 9 connection ) ! signal+1 telephone & fire al>m sy/em4 ,! tunnel is light$ ) #hjj #af-;c&le-p[] inc&esc5t lights4 ,! track con/ruction is new4 ,!re is no balla/ us$1 ! ties be+ laid 9 concrete4 ,a dit* 9 ! c5t] ( ea* track c>ries ! ra9fall t w fl[ d[n f ! summits to sumps :i* are dra9$ by c5trifugal pumps4 ,"o rem>kable feature ( its con/ruction is t compress$ air 0 n us$ 9 ! build+ ( ! subaque\s tunnel1 b x 0 necess>y 9 build+ ! approa* tunnels4 ,?is is contr>y to ! usual program :]e compress$ air is requir$ 9 subaque\s "w1 & n ord9>ily us$ 9 approa* or l& tunnel con/ruction4 ,! tra9s are op]at$ by v heavy electric locomotives1 op]at$ by ! ?ird-rail sy/em4 ,! tunnel 0 con/ruct$ "u ! sup]vision ( ,w4 ,s4 ,k9ne>1 ,*ief ,eng9e] ( ! ,detroit ,riv] ,tunnel ,co42 ,butl] ,bros4 ( ,new ,york 7 ! g5]al contractors4 ,,*apt] ,,xxii4 ,,accid5ts ,,& ,,repairs ,,9 ,,tunnels ,,dur+ ,,& ,,aft] ,,con/ruction4 ,9 ! excavation ( tunnels x (t5 happ5s t ! di/urbance ( ! equilibrium ( ! surr\nd+ mat]ial by ! excavation develops =ces ( su* int5sity t ! timb]+ or l9+ is cru%$ & ! tunnel de/roy$4 ,to provide aga9/ accid5ts ( ?is k9d 9 a !oretically p]fect mann] w\ld require ! eng9e] to h an accurate k ( ! "*1 direction & int5sity ( ! =ces develop$1 & ?is is practically impossible1 s9ce all ( ^! factors diff] ) ! nature & /ructure ( ! mat]ial p5etrat$4 ,! be/ t c be done1 !re=e1 is to det]m9e ! g5]al "* & /ructure ( ! mat]ial p5etrat$1 z fully z practicable1 by means ( bor+s & geological surveys1 & !n to employ timb]+ & masonry ( su* dim5sions & "* z h )/ood successfully ! pressures develop$ 9 previ\s tunnels excavat$ ?r\gh simil> mat]ial4 ,if1 despite ^! precautions1 accid5ts occur1 ! eng9e] is compell$ to devise me?ods ( *eck+ & repair+ !m1 & x is ! purpose ( ?is *apt] to po9t out briefly ! mo/ common k9ds ( accid5ts1 _! causes1 & ! usual me?ods ( repair+ !m4 ,accid5ts ,dur+ ,con/ruction4--,accid5ts may happ5 bo? dur+ or aft] con/ruction1 b x is dur+ con/ruction1 :5 ! equilibrium ( ! surr\nd+ mat]ial is fir/ di/urb$1 & :5 ! only support ( ! pressures develop$ is ! timb] /rutt+ t !y mo/ commonly occur4 ,causes ( ,collapse4--,collapse 9 tunnels may be caus$3 7#a7 by ! weight ( ! e>? ov]head1 :i* is left unsupport$ by ! excavation2 7#b7 by defective or insuffici5t /rutt+2 & 7#c7 by defective or weak masonry4 7#a7 ,! dang] ( collapse ( ! ro( ( ! excavation is influ5c$ by sev]al conditions4 ,"o ( ^! is ! me?od ( excavation adopt$4 ,x is obvi\s t ! l>g] ! volume ( ! support+ e>? is1 :i* is remov$1 ! great] w be ! t5d5cy ( ! ro( to fall1 & ! m int5se w be ! pressures :i* ! /rutt+ w be call$ ^u to support4 ,?us ! ,engli% & ,au/rian me?ods ( tunnel+1 :]e ! full section is excavat$ be=e any ( ! l9+ is plac$1 & :]e1 z ! consequ5ce1 ! /rutt+ has to su/a9 all ( ! pressures1 pres5t m likelihood ( ! ro( cav+ 9 ?an any ( ! o!r common me?ods4 ,! "* & /ructure ( ! mat]ial p5etrat$ also influ5ce ! dang] ( a collapse4 ,a loose soil ) little cohesion is ( c\rse m likely to cave ?an "o :i* is m /able4 ,rock :]e /rata are horizontal1 or :i* is seamy & fissur$1 is m likely to break d[n "u ! ro( pressures ?an "o ) v]tical /rata & ( homog5e\s /ructure4 ,s(t sod conta9+ b\ld]s ^: weight develops local /resses 9 ! ro( timb]+ is likely to be m dang]\s ?an "o :i* is m homog5e\s4 ,a factor :i* greatly increases ! dang] ( collapse1 especially 9 s(t soils1 is ! pres5ce ( wat]4 ,?is elem5t (t5 *anges a soil :i* is comp>atively /able1 :5 dry1 into "o :i* is highly un/able & trea*]\s4 ,! liability ( ! mat]ial to dis9tegration by atmosph]ic influ5ces & v>i\s o!r conditions1 :i* w occur to ! read]1 may influ5ce its /ability to a dang]\s ext5t1 & result 9 collapse4 7#b7 ,collapse is (t5 ! result ( us+ defective or insuffici5t /rutt+4 ,( c\rse1 9 "o s5se1 any /rutt+ :i* fails "u ! pressures develop$1 h[ev] enorm\s !y may be1 c be said to be insuffici5t1 b z us$ "h ! t]m means a /rutt+ ) an insuffici5t factor ( safety to meet probable increases or v>iations 9 pressure4 ,insuffici5t /rutt+ may be due to ! use ( too light timb]s1 to ! spac+ ( ! ro( timb]s too f> ap>t1 to ! yield+ ( ! f\ndations1 to insuffici5t be>+ surface at ! jo9ts1 etc4 ,collapse is (t5 caus$ by ! premature removal ( ! /rutt+ dur+ ! con/ruction ( ! masonry4 ,! masons1 to secure m free space 9 :i* to "w1 are v likely1 unless wat*$1 to remove too _m ( ! timb]s & s]i\sly weak5 ! /rutt+4 7#c7 ,! ?ird cause ( collapse is badly built masonry4 ,poor masonry may be due to ! use ( defective /one or brick1 to ! ?9ness ( ! l9+1 to poor mort>1 to weak c5t]s :i* all[ ! ar* to become di/ort$ dur+ con/ruction1 to poor bond+ ( ! /one or bricks1 to ! premature removal ( ! c5t]s1 to driv+ "s ( ! ro( timb]s inside x1 etc4 ,prev5tion ( ,collapse4--,tunnels v seldom collapse )\t giv+ "s previ\s w>n+ ( ! possible failure1 & also ( ! mann] 9 :i* ! failure is likely to occur4 ,f ^! indications ! eng9e] is (t5 able to =esee ! nature ( ! dang] & take /eps to *eck x4 ,! dang] may occur ei!r dur+ excavation or aft] ! l9+ is built4 ,dur+ excavation ! dang] ( collapse is indicat$ be=eh& by ! p>tial cru%+ or deflection ( ! /rutt+ timb]s4 ,if ! timb]s are too light or ! be>+ surfaces are too small1 cru%+ takes place :]e ! pressures are ! greate/1 & ! timb]s b5d1 bur/1 or crack 9 places1 & ! jo9ts op5 9 o!r places4 ,! rem$y 9 su* cases is to ins]t additional timb]s to /r5g!n ! weak po9ts1 or x may be necess>y to con/ruct a d\ble /rutt+ ?r\gh\t4 ,:5 ! di/ance spann$ by ! ro( timb]s is too great1 failure is g5]ally indicat$ by ! excessive deflection ( ^! timb]s1 & ?is may (t5 be rem$i$ by ins]t+ int]m$iate /ruts or props4 ,9 "s respects ! be/ rem$y "u any ( ^! conditions is to con/ruct ! masonry z soon z possible4 ,:5 collapse is likely to occur aft] ! masonry is complet$1 its probability is g5]ally indicat$ by ! crack+ & di/ortion ( ! l9+4 ,a /udy ( ! cause is q likely to %[ t x is ! p]colation ( wat] ?r\gh ! mat]ial surr\nd+ ! l9+ :i* causes cavities beh9d ! l9+ 9 "s places1 & an increase ( ! pressures 9 o!r places4 ,:5 x is c]ta9 t ?is wat] comes f ! surface /reams above1 ^! /reams may (t5 be div]t$ or h _! b$s l9$ ) concrete to prev5t fur!r p]colation4 ,:5 p]colat+ wat] is n ! cause ( ! tr\ble1 a usually effici5t rem$y is to s9k a %aft ov] ! weak po9t1 & refill x ) mat]ial ( m /able "*4 ,^!1 & ! rem$ies previ\sly sugge/$1 are design$ to prev5t failure )\t resort+ to recon/ruction4 ,:5 !y or simil> means prove insuffici5t1 recon/ruction or repairs h to be resort$ to4 ,repair+ ,failures4--,tunnels may collapse 9 sev]al ways3 7#a7 ,! front & sides ( ! excavation may cave 92 7#b7 ! floor or bottom may bulge or s9k2 7#c7 ! ro( may fall 92 7#d7 ! mat]ial above ! entrances may slide & fill !m up4 7#a7 ,"o ( ! mo/ common accid5ts is ! cav+ ( ! front & sides ( ! excavation4 ,?is may (t5 be prev5t$ by tak+ c>e t ! face ( ! excavation foll[s ! natural slope ( ! mat]ial in/ead ( be+ m or less ne>ly v]tical4 ,:51 h[ev]1 cav+ does occur x may usually be repair$ by remov+ ! fall5 mat]ial1 /rongly %or+ ! cavity1 & fill+ 9 beh9d ) /one1 timb]1 or fasc9es4 7#b7 ,! bulg+ or ris+ ( ! bottom ( ! tunnel may usually be consid]$ z a consequ5ce ( ! squeez+ toge!r ( ! side walls4 ,x usually occurs 9 v loose soils1 & is *iefly important f ! fact t ! recon/ruction ( ! side walls is made necess>y4 ,! s9k+ ( ! tunnel bottom is a m s]i\s occurr5ce4 ,x seldom happ5s unless !re is a cavity b5ea? ! floor1 due ei!r to natural causes or to ! fact t m9+ op]ations h gone on 9 ! hill or m\nta9 p5etrat$ by ! tunnel4 ,:5 ! bottom ( ! tunnel s9ks1 ?ree cases may be consid]$3 7a7 :5 ! s9k+ is limit$ to ! middle ( ! tunnel floor2 7b7 :5 only a portion ( ! f\ndation masonry is affect$2 &1 7c7 :5 ! entire l9+ is di/urb$4 ,9 ! fir/ case repairs are easily made by fill+ 9 ! cavity ) new mat]ial4 ,9 ! second case ! unimpair$ portion ( ! masonry is tempor>ily support$ by %or+ :ile ! injur$ portion is remov$ & rebuilt on a firm f\ndation4 ,! rema9+ cavity is !n fill$4 ,9 ! case ( ! complete failure ( ! l9+1 ! me?od ( repair+ employ$ :5 ! ro( falls1 & describ$ bel[1 is usually adopt$4 7#c7 ,! mo/ dang]\s ( all failures is ! fall+ ( ! tunnel ro(4 ,9 su* casualties two cases may be consid]$3 7a7 ,:5 ! fall+ mass completely fills ! tunnel section1 & 7b7 :5 x fills only a portion ( ! section4 ,illu/ration3 ,,fig4 #aeb4--,tunnel+ ?r\gh ,cav$ ,mat]ial by ,head+4 ,:5 ! :ole section is fill$ by ! fall5 mat]ial1 ! problem may be consid]$ z ! excavation ( a new tunnel ( %ort l5g? inside ! old tunnel1 & "u r m difficult conditions4 ,! fir/ task1 p>ticul>ly if m5 h be5 imprison$ beh9d ! fall5 mat]ial1 is to op5 communication ?r\gh x betwe5 ! two un9jur$ portions ( ! tunnel4 ,x is advisable to d ?is ev5 :5 !re is no dang] to life because ( imprison$ workm51 s9ce x enables ! "w ( repair+ to be conduct$ f bo? directions4 ,! excavation ( a passageway ?r\gh ! fall5 mat]ial is r5d]$ difficult1 bo? because ! fall5 mat]ial is ( an un/able "*1 & also because x is usually fill$ ) ! l9+ masonry1 timb]+1 etc4 ,:51 !re=e1 ! accid5t has happ5$ be=e ! full section ( ! orig9al mat]ial has be5 remov$1 ! fir/ head+ or drift is driv5 ?r\gh ?is orig9al mat]ial r ?an ?r\gh ! fall5 dbris4 ,any ( ! regul> s(t-gr\nd me?ods ( tunnel+ may be employ$1 b x is usually bett] to select "o :i* all[s ! masonry to be built ) z little excavation z possible at fir/4 ,= ?is reason ! ,g]man me?od ( tunnel+ is p>ticul>ly suit$ to repair "w ( ?is nature4 ,! ,belgian me?od may also be us$ to advantage1 p>ticul>ly :5 ! cav+ ext5ds to ! surface ( ! gr\nd above1 & ! upp] portion ( ! dbris is1 !re=e1 practically ! same mat]ial z t ?r\gh :i* ! orig9al tunnel 0 driv54 ,! greate/ defect ( ! ,belgian me?od = mak+ repairs is t ! ro( ar* is support$ by a r un/able mass ( m+l$ e>?1 /one1 & timb]1 :i* con/itutes ! bottom lay] ( ! fall5 mat]ial4 ,! me?od ( /rutt+ ! "w :5 ! ,g]man or ,belgian me?od is us$ is %[n by ,fig4 #aeb4 ,x sometimes happ5s t ! fall5 dbris is s un/able t x w n c>ry safely ! ar* masonry 9 ! ,belgian me?od or ! /rutt+ 9 ! ,g]man me?od1 & 9 ^! cases "o ( ! full-section me?ods ( excavation is usually adopt$4 ,! nature ( ! /rutt+ employ$ is %[n by ,fig4 #aec4 ,:5 ! section has be5 op5$ & ! new masonry built1 great c>e %\ld be tak5 to fill ! cavity beh9d ! masonry ) timb] or /one2 & %\ld ! di/urbance rea* to ! gr\nd surface x is (t5 a good plan to s9k a %aft ?r\gh ! di/urb$ mat]ial1 & fill x ) m /able mat]ial4 ,illu/ration3 ,,fig4 #aec4--,tunnel+ ?r\gh ,cav$ ,mat]ial by ,drifts4 ,:5 ! fall5 dbris fills only a "p ( ! section1 ! fir/ ?+ to provide aga9/ is ! occurr5ce ( any fur!r cav+2 & ?is is usually done by build+ a protect+ ro( above ! l9e ( ! future ro( masonry4 ,figs4 #aed & #aee %[ two me?ods ( con/ruct+ ?is tempor>y ro(1 :i* x w be notic$ is fill$ above ) cordwood pack+4 ,z soon z ! tempor>y ro( is complet$1 ! l9+ masonry is con/ruct$4 ,illu/ration3 ,,figs4 #aed & #aee4--;,fill+ 9 ,ro( ,cavity ,=m$ by ,fall+ ,mat]ial4 ,illu/ration3 ,,fig4 #aef4--,timb]+ to ,prev5t ,l&slides at ,portal4 7#d7 ,l&slides :i* close ! tunnel entrance are repair$ 9 a v>iety ( ways4 ,fig4 #aef %[s a common me?od ( prev5t+ ! ext5sion ( a l&slide :i* has be5 />t$ by ! excavation = ! entrance masonry4 ,fig4 #aeg %[s a me?od (t5 adopt$ :5 ! slope is q flat & ! am\nt ( slid+ mat]ial is small4 ,x consi/s ess5tially ( remov+ ! fall5 mat]ial & build+ a new portal f>!r back2 t is1 ! op5 cut is ext5d$ & ! tunnel is %ort5$4 ,:5 ! am\nt ( ! slid+ mat]ial is v l>ge1 ! contr>y practice ( l5g!n+ ! tunnel & %ort5+ ! op5 cut1 z %[n by ,fig4 #aeh1 may be adopt$4 ,illu/ration3 ,,fig4 #aeg4--,%ort5+ ,tunnel ,cru%$ by ,l&slide at ,portal4 ,accid5ts ,aft] ,con/ruction4--,accid5ts aft] ! completion ( ! tunnel may be divid$ into two classes3 fir/1 ^? :i* entirely ob/ruct ! passage ( tra9s1 ( :i* ! collapse ( ! ro( is ! mo/ common2 & second1 ^? :i* all[ traffic to be cont9u$ :ile ! repairs are be+ made1 su* z ! bulg+ inw>d ( a portion ( ! l9+ )\t total collapse4 ,9 ! fir/ case ! fir/ duty ( ! eng9e] is to op5 communication ?r\gh ! fall5 dbris1 s t pass5g]s at lea/ may be transf]r$ f "o "p ( ! tunnel to ! o!r & proce$ on _! way4 ,?is is done by driv+ a head+1 & /rongly timb]+ x to s]ve z a passageway4 ,if ! tunnel is s+le track$ ?is head+ is aft]w>ds enl>g$ until ! :ole section is op5$4 ,9 d\ble-track tunnels ! me?od g5]ally adopt$ is to op5 fir/ "o side ( ! section & timb] x /rongly1 s z to cle> "o track = traffic4 ,:ile ! tra9s are runn+ ?r\gh ?is tempor>y passageway ! o!r half ( ! section is op5$ & repair$2 ! traffic is !n %ift$ to ! new p]man5t track1 & ! tempor>y /ructure fir/ employ$ is replac$ ) a p]man5t l9+4 ,:5 ! accid5t is su* t ! repairs c be made )\t ob/ruct+ traffic entirely1 v>i\s modes ( proc$ure are foll[$4 ,9 all cases great c>e has to be ex]cis$ to prev5t accid5t to ! tra9s & to ! tunnel workm54 ,! "w %\ld be done 9 small sections s z to di/urb z little z possible ! already tr\bl$ equilibrium ( ! soil2 ! /rutt+ %\ld be plac$ s z to give ample cle>+ space to pass+ tra9s1 & ! tra9s !mselves %\ld be run at sl[ spe$s pa/ ! site ( ! repairs4 ,to illu/rate ! two k9ds ( accid5ts & ! me?ods ( repair+ !m1 :i* h be5 m5tion$1 ! accid5ts at ! ,giovi tunnel 9 ,italy & at ! ,*attanooga tunnel 9 ,am]ica h be5 select$4 ,illu/ration3 ,,fig4 #aeh4--;,ext5d+ ,tunnel ?r\gh ,l&slide at ,portal4 ,giovi ,tunnel ,accid5t4--,9 ,septemb]1 #ahfi1 at a po9t ab\t #bbj ft4 f ! s\? portal ( ! ,giovi tunnel1 a di/urbance ( ! masonry l9+ = a l5g? ( ab\t #eb ft4 0 obs]v$4 ,accurate measurem5ts %[$ t ! l9+ 0 n symmetrical ) respect to ! v]tical axis ( ! sectional pr(ile4 ,x 0 conclud$ t ow+ to "s di/urbance ( ! surr\nd+ soil unsymmetrical v]tical & lat]al pressures 7 act+ on ! masonry4 ,close wat* 0 kept ( ! di/ort$ masonry1 :i* = "s "t rema9$ un*ang$ 9 position4 ,9 #ahgb1 h[ev]1 new crevices 7 obs]v$ to h develop$1 & %ortly aft]w>ds1 9 ,janu>y1 #ahgc1 ! injur$ portion ( ! masonry cav$ 91 ob/ruct+ ! :ole tunnel section4 ,! fall5 mat]ial consi/$ *iefly ( clay 9 a ne>ly pla/ic /ate4 ,! surface ( ! gr\nd above 0 obs]v$ to h settl$4 ,inve/igation %[$ also t ! cause ( ! cav+ 0 ! p]colation ( wat] f a ne>by creek4 ,! wat] _h soak$ ! gr\nd1 & decreas$ its /ability to su* an ext5t t ! masonry l9+ 0 unable to )/& ! increas$ v]tical & lat]al pressures4 ,! mode ( proc$ure decid$ ^u = repair+ ! damage 03 7#a7 ,to op5 at lea/ "o track = ! tempor>y accommodation ( traffic2 7#b7 ,to remove p]man5tly ! causes :i* _h produc$ ! collapse2 7#c7 ,to build a new & mu* /rong] l9+4 ,close to ! we/]n side wall1 :i* 0 /ill /&+1 ! dbris 0 remov$1 & ! op5+ /rongly /rutt$ 9 ord] to all[ ! lay+ ( a s+le track to re/abli% communication4 ,at ! same "t a %aft 0 sunk f ! surface above ! cav$ portion ( ! tunnel1 = ! d\ble purpose ( facilitat+ ! removal ( ! fall5 mat]ial & ( af=d+ v5tilation4 ,! dep? ( ! surface above ! tunnel 0 #da4f ft41 :i* made ! con/ruction ( ! %aft a comp>atively easy matt]4 ,! %aft itself 0 #f ft4 wide & #ah ft4 long1 ) its long] dim5sions p>allel to ! tunnel1 & x 0 l9$ ) a rectangul> horizontal frame & v]tical-pol+ bo>d con/ruction4 ,aft] tempor>y communication _h be5 op5$ on ! we/]n track ( ! tunnel1 ! rema9d] ( ! fall5 e>? 0 remov$ & ! excavation /rutt$4 ,! new masonry l9+ 0 !n built4 ,to remove p]man5tly ! cause ( ! cave-91 :i* 0 ! p]colation ( wat] f a close-by /ream1 ?is /ream 0 div]t$ to a new *annel con/ruct$ ) a concrete b$ & side walls4 ,! failure ( ! orig9al l9+ occurr$ by cracks develop+ at ! cr[n1 haun*es1 & spr++ l9es4 ,! new l9+ 0 made consid]ably ?ick] ?an ! orig9al l9+1 & at ! po9ts :]e failure _h fir/ occurr$ 9 ! orig9al ar* cut-/one v\ssoirs 7 ins]t$ 9 ! brickwork ( ! new ar* z describ$ 9 ,*apt] ,,xiii4 ,*attanooga ,tunnel4--,! ,we/]n ,atlantic ,ry4 passes ?r\gh ! ,*attanooga m\nta9s by means ( a s+le-track tunnel #a1dgg ft4 long1 con/ruct$ 9 #ahdh-di4 ,! l9+ consi/$ ( a brickwork ro( ar* & /one masonry side walls4 ,aft] ! tunnel _h be5 op5$ to traffic1 ?is l9+ bulg$ inw>d at places1 contract+ ! tunnel section to su* an ext5t t x 0 decid$ to recon/ruct ! di/ort$ portions4 ,aft] c>eful surveys & calculations _h be5 made1 x 0 decid$ to take d[n & recon/ruct ab\t #agj ft4 ( ! l9+4 ,ow+ to contract$ space 9 ! tunnel1 x 0 necess>y to remove all m51 tools1 & mat]ial1 :5ev] tra9s 7 to pass ?r\gh2 & 9 ord] to d ?is a "w-tra9 ( ?ree c>s 0 fitt$ up ) necess>y scaffolds1 & suppli$ ) gasol9e tor*es = light+ purposes4 ,mort> 0 mix$ on ! c>s1 & all mat]ial rema9$ on !m until us$4 ,dbris torn out ( ! old wall 0 load$ on ! c>s1 & haul$ to ! wa/e dump4 ,a sid+ 0 built ne> ! ,we/ end ( ! tunnel = ! use ( ?is tra91 & a telephone sy/em 0 in/all$ betwe5 ! entrances & ! work+-tra94 ,on acc\nt ( ! contract$ work+-space & ! great] ease ) :i* brick c\ld be h&l$1 x 0 decid$ to rebuild ! walls out ( brick in/ead ( /one4 ,9 te>+ out ! old wall a hole 0 fir/ cut ?r\gh ! ?ree bottom c\rses ( ! ar* & gradually wid5$4 ,:5 ! op5+ became f\r or five feet long1 a small jack 0 plac$ ne> ! c5t] ( x & br\ght to a be>+ aga9/ ! ar* to su/a9 x4 ,aft] cutt+ ! op5+ to a l5g? ( f #g to #aj ft4 dep5d+ on ! /ability ( ! e>? back+1 ! jack 0 remov$ & a piece ( #haf 94 timb] plac$ "u ! ar* & br\ght up to a be>+ ) jacks4 ,"o end ( ! timb] re/$ on ! old wall1 ! o!r on a seat built into ! adjo9+ section ( new wall4 ,w$ges 7 !n driv5 "u ! ends ( timb] & ! jacks remov$4 ,) ?is timb] 9 place1 ! old wall c\ld be tak5 d[n ) ease1 ! only tr\ble be+ t small /ones & e>? fell 9 f above & beh9d ! ar*4 ,?is 0 obviat$ by plac+ a #b 94 plank across ! op5+ & j back ( ! #haf 94 timb]4 ,at sev]al po9ts1 h[ev]1 ! e>? back+ 0 saturat$ ) wat]1 & x became necess>y to put 9 lagg+ z ! old wall 0 remov$4 ,?is timb]+ w\ld be tak5 out z ! new "w 0 built up4 ,a suitable f\ndation = ! new wall 0 secur$ at a dep? f #b to #d ft41 & a concrete foot+ 0 us$4 ,! section ( ! new wall 0 !n built up z ne> z possible to ! #haf 94 timb]2 ! timb] 0 !n remov$ & ! new wall built up & key$ "u ! ar*4 ,! new wall _h a m9imum wid? ( #b ft4 at ! top1 & #d ft4 at ! base ( rail1 & 0 provid$ ) weep holes at int]vals4 ,to facilitate matt]s1 "w 0 c>ri$ on simultane\sly at two or ?ree diff]5t places1 ! int5tion be+ to get "o place torn out & ready = ! bricklay]s by ! "t !y complet$ a section ( ! new wall at ano!r place4 ,9 rebuild+ ! ar*1 sections ext5d+ f ! spr++ l9e up z f> z 0 necess>y to obta9 ! desir$ cle>ance1 & f #b to #d ft4 9 l5g?1 7 remov$4 ,ne> ! sides1 ! e>? above ! ar* 0 a /iff clay1 :i* 0 self-su/a9+2 b ne> ! c5t] !re occurr$ a /ratum ( gravel & clay saturat$ ) wat]4 ,?is gave consid]able tr\ble1 fall+ ?r\gh almo/ cont9u\sly until timb]+ c\ld be plac$4 ,"o end ( ?is timb] re/$ on ! old ar*1 ! o!r on ! adjo9+ section ( ! new "w4 ,z ! new "w 0 to be set #f to #ac ins4 back f ! old1 x 0 necess>y to block up ?is di/ance on top ( ! old ar*1 to c>ry ! end ( ! lagg+ timb]1 9 ord] t ! timb] %\ld be cle> ( ! new ar*4 ,ow+ to ! small cle>ance betwe5 ! c> ro( & ! ar*1 a special =m ( c5t]+ 0 requir$1 "o t w\ld occupy z small space z possible4 ,b> iron #a 94 ?ick1 #d ins4 wide1 & #bj ft4 long 0 curv$ to a radius ( #f ft41 & on ! und]side ( ?is 0 rivet$ a #f-;94 plate 94 ?ick4 ,?is plate project$ #a 94 on ! sides ( ! c5t]+1 & c>ri$ ! ends ( ! #a 94 bo>ds us$ = lagg+4 ,! rivets 7 c\nt]-sunk on ! outside ( ! c5t]+ to pres5t a smoo? surface next ! ar*4 ,9 key+ up a section ( ! new "w1 a space ab\t #ah ins4 squ>e _h to be left op5 = ! use ( ! workm54 ,z soon z ! next section _h be5 torn out1 ?is space 0 built up4 ,9 build+ up ! la/ section1 ?is space _h to be fill$ f bel[1 :i* prov$ to be a t$i\s und]tak+4 ,! op5+ 0 gradually r$uc$ to a size ( #aj #ah 941 & ! top r+ !n complet$ & key$ up1 ! adhesion ( mort> hold+ ! bricks 9 place until ! key c\ld be driv5 home4 ,! next r+ 0 treat$ 9 a simil> mann]1 & s on to ! face r+4 ,altoge!r #dab l94 ft4 ( ! walls & #agh l94 ft4 ( ! ar* 7 tak5 d[n & rebuilt1 am\nt+ 9 all to #fjg cu4 yds4 ( masonry at ! total co/ ( #g1ddj1 or ab\t #ab4be p] cu4 yds4 ,! regul> tra9s arriv$ s frequ5tly at ! tunnel t slightly ov] two h\rs 0 ! longe/ work+-"t betwe5 any two tra9s1 & usually less ?an "o h\r at a "t 0 all t x c\ld be work$4 ,9 addition to ! regul> tra9s1 a l>ge numb] ( extra tra9s1 mov+ troops1 _h to be accommodat$4 ,"w 0 9 progress eight mon?s1 & dur+ t "t !re 0 no delay to a pass5g] tra94 ,! repairs 7 complet$ 9 ,augu/1 #ahii4 ,! "w 0 "u ! direction ( ,mr4 ,w4 ,h4 ,:orley1 eng9e] ( ! ,we/]n ,atlantic ,r4 ,r41 & =eman ( con/ruction1 ,a4 ,h4 ,ri*>ds4 ,a rec5t exam9ation fail$ to reveal any sign ( settlem5t cracks at ! junction po9ts ( ! new & old "w4 ,,*apt] ,,xxiii4 ,,rel9+ ,,timb]-,,l9$ ,,tunnels ,,) ,,masonry4 ,! orig9al con/ruction ( _m ,am]ican railway tunnels ) a timb] l9+ to r$uce ! co/ & ha/5 ! "w has made x necess>y to rel9e !m1 z "t has pass$1 ) "s m p]man5t mat]ial4 ,9 mo/ cases ! "w ( remov+ ! old l9+ & replac+ x ) ! new masonry has _h to be done )\t int]f]+ ) ! runn+ ( tra9s1 & a numb] ( +5i\s me?ods h be5 develop$ by eng9e]s = accompli%+ ?is task4 ,?ree ( ^! me?ods :i* h be5 employ$1 respectively1 9 rel9+ ! ,b\ld] tunnel on ! ,montana ,c5tral ,ry41 9 ,montana1 ! ,mullan tunnel on ! ,nor!rn ,pacific ,ry41 9 ,montana1 & ! ,little ,tom tunnel on ! ,norfolk ,we/]n ,r4 ,r41 9 ,virg9ia1 h be5 select$ z fairly repres5tative ( ?is class ( tunnel "w4 ,b\ld] ,tunnel4--,?is tunnel p5etrates a spur ( ! ma9 range ( ! ,rocky ,m\nta9s1 at an elevation at ! summit ( grade ( #e1ded ft41 & is #f1aab ft4 9 l5g?4 ,its alignm5t is a tang5t1 ) ! exception ( #aej ft4 ( #cj curve at ! nor? end4 ,! mat]ial p5etrat$ is blue trap-rock ) seams = #d1iej ft4 f ! nor? end1 & sy5itic b\ld]s ) ! int]v5+ spaces fill$ ) dis9tegrat$ mat]ial = ! rema9+ #a1afj ft4 ,! dim5sions & "* ( ! old timb] l9+ & ( ! new masonry l9+ replac+ x are %[n 9 ,figs4 #aei & #afj4 ,! =m ( masonry adopt$ consi/$ ( co>se rubble side walls ( granite1 #ac ft4 #h ins4 high1 & g5]ally #bj ins4 ?ick1 ) a full c5t] circul> ar* ( f\r r+s ( brick laid 9 r[lock =m4 ,:5 great] /r5g? 0 ne$$ ! ?ickness ( ! side walls 0 increas$ to #cj ins4 & t ( ! ar* to six r+s ( brick4 ,illu/ration3 ,cross ,section4 ,longitud9al ,section4 ,cross ,section4 ,cross ,section4 ,,figs4 #aei & #afj4--,rel9+ ,timb]-,l9$ ,tunnel4 ,! fir/ plan adopt$ 9 putt+ 9 ! masonry 0 to remove all ! timb]+2 b ow+ to ! l>ge numb] ( falls & slides ?is 0 ab&on$1 & ! plan foll[$ 0 to leave 9 ! ?ree ro( segm5ts ( ! timb]+ ) ! ov]ly+ cord-wood pack+ & dbris4 ,9 c>ry+ on ! "w ! fir/ /ep 0 to remove ! side timb]s4 ,?is 0 done by support+ ! ro( timb]s1 z %[n 9 ,fig4 #aei2 t is1 ! fir/ & f\r? ar* rib ( an #h-;ft4 section conta9+ f\r ar* ribs 7 support$ by tempor>y po/s4 ,! int]m$iate ar* ribs 7 support$ aga9/ ! d[nw>d pressure by #f #f 94 timb]s1 ext5d+ f ! side ribs ne> ! tops ( ! tempor>y po/s to ! opposite sides ( ! int]m$iate ro( segm5ts1 z %[n 9 ! longitud9al section1 ,fig4 #afj4 ,to resi/ ! pressure f ! sides1 #d #f 94 braces 7 plac$ across ! tunnel f ne> ! c5t] ( ! int]m$iate segm5ts to ! upp] ends ( ! hip segm5ts1 z %[n 9 ! cross-section1 ,fig4 #aei4 ,! hip segm5ts 7 !n saw$ (f bel[ ! not*1 & ! side timb]+ remov$ & ! masonry built4 ,! /one 0 convey$ into ! tunnel on flat c>s1 & laid by means ( small d]ricks locat$ on ! c>s4 ,two d]ricks 7 us$1 "o = ea* side wall1 & ! "w on bo? walls 0 c>ri$ on simultane\sly4 ,! ar* 0 built ^u a c5t]+1 ! ribs ( :i* 7 #e ins4 less 9 diamet] ?an ! di/ance betwe5 ! side walls1 s z to p]mit ! use ( #b ins4 lagg+4 ,ea* c5t] _h ?ree ribs1 made 9 #a-;94 or #b-;94 bo>d segm5ts1 #aj ins4 ?ick & #ad ins4 deep4 ,^! ribs 7 m\nt$ on frames1 :i* foll[$ ! opposite walls1 & 7 #d ft4 ap>t1 mak+ ! total l5g? ( ! c5t] out to out ab\t #i ft4 ,! frames1 ^u :i* ! ribs 7 support$1 are %[n 9 ,fig4 #afa4 ,z w be se51 !y 7 m\nt$ on dollys to enable ! c5t] to be mov$ f "o section to ano!r4 ,jacks 7 us$ to raise & l[] ! c5t] into its prop] position4 ,illu/ration3 ,cross ,section4 ,longitud9al ,section4 ,,fig4 #afa4--,rel9+ ,timb]-,l9$ ,tunnel1 ,great ,nor!rn ,ry4 ,! ar* 0 built up f ! spr++ l9es on bo? sides at ! same "t1 f\r masons be+ employ$4 ,! r+s 7 built beg9n+ ) ! intrados1 :i* 0 br\ght up1 say1 a di/ance ( ab\t #b ft4 f ! spr++ l9e4 ,!n ! back ( ! r+ 0 well pla/]$ ) f 94 to 94 ( mort>1 & ! second r+ br\ght up to ! same height & pla/]$ on ! back1 & s on until ! la/ r+ 0 laid4 ,aft] br++ ! full wid? ( ! ar* up "s di/ance1 new lagg+s 7 plac$ on ! ribs = an additional height ( #b ft4 & ! same process 0 repeat$4 ,all ! space betwe5 ! extrados ( ! masonry ar* & ! old l9+ 0 compactly fill$ ) dry rubble4 ,:5 high en\gh s t ! hip segm5ts _h a foot or m be>+ on ! masonry ! segm5ts 7 securely w$g$ & block$ up aga9/ ! brickwork1 & ! longitud9al #d #f 94 timb]s remov$4 ,! rema9+ space 0 n[ cle> = completion ( ! ar*1 & bo? sides 7 br\ght up until !re 0 n suffici5t space = f\r masons to "w1 :5 ! key+ 0 complet$ by two masons beg9n+ at ! complet$ & work+ back t[>d ! too!d end4 ,! brickwork 0 built f ! top ( a /ag+-c>4 ,illu/ration3 ,cross ,section4 ,longitud9al ,section4 ,,fig4 #afb4--,rel9+ ,timb]-,l9$ ,tunnel1 ,great ,nor!rn ,ry4 ,9 a few in/ances :]e slides occurr$ aft] ! removal ( ! slide timb]+1 ! me?od ( re timb]+ ! tunnel %[n 9 ,fig4 #afb 0 adopt$4 ,two side drifts 7 fir/ run #b ft4 wide by #d ft4 high1 & ! plate timb]s plac$ 9 position & block$4 ,cross drifts 7 !n run1 & ! ro( segm5ts plac$1 & ! core d[n to ! level ( ! bottoms ( ! side drifts tak5 out4 ,! l[] wall plates 7 !n plac$ & ! hip segm5ts ins]t$4 ,! b5* 0 !n tak5 d[n by degrees1 ! side plates be+ held by jacks1 & ! po/s plac$ "o at a "t4 ,z ! masonry at ! po9ts :]e slides occur consi/s ( #cj-;94 walls & six-r+ ar*1 ! timb]+ 0 #bb ft4 wide 9 ! cle>1 ) o!r dim5sions z %[n 9 ,fig4 #afb4 ,only a s+le crew ( brick & /one masons 0 employ$4 ,9 ord] to prep>e ! sections = ^! masons x 0 necess>y to h timb] & trimm+ crews at "w ?r\gh\t ! :ole day ( #bd h\rs1 s t an eng9e & two tra9 crews 7 9 con/ant att5dance4 ,! s+le mason crews 7 able to complete #h ft4 ( side wall & ar* 9 #bd h\rs4 ,! numb] ( m5 actually employ$ at ! tunnel 0 #ce4 ,?is includ$ electric-light ma9t5ance1 & all o!r labor p]ta9+ to ! "w4 ,! tunnel 0 light$ by an ,edison dynamo ( #bj arc light capacity1 "o arc light be+ plac$ on ea* side ( ! tunnel at all work+-places4 ,ea* lamp c>ri$ a coil ( wire #bj or #cj ft4 long to all[ x to be %ift$ f place to place )\t delay4 ,mullan ,tunnel4--,?is tunnel is #c1hej ft4 long1 & crosses ! ma9 range ( ! ,rocky ,m\nta9s1 ab\t #bj miles we/ ( ,hel5a1 ,mont4 ,! tunnel is on a tang5t ?r\gh\t1 & has a grade ( #bj fall+ t[>d ! ea/4 ,! summit ( ! grade1 we/ ( ! tunnel1 is #e1edh ft4 above sea level1 & ! m\nta9 above ! l9e ( ! tunnel rises to an elevation ( #e1hee ft4 ,ow+ to ! trea*]\s nature ( ! mat]ial ?r\gh :i* ! tunnel pass$1 x _h be5 a con/ant m5ace to traffic ev] s9ce its con/ruction 9 #ahhc1 & num]\s delays to tra9s _h be5 caus$ by ! falls ( rock & fires 9 ! timb] l9+4 ,= ^! reasons x 0 f9ally decid$ to build a p]man5t masonry l9+1 & "w on ?is 0 begun 9 ,july1 #ahib4 ,illu/ration3 ,) ,wall ,plates4 ,)\t ,wall ,plates4 ,old ,timb] ,sections4 ,m9imum ,section4 ,av]age ,section4 ,p]man5t ,"w4 ,,fig4 #afc4--,rel9+ ,timb] ,l9$ ,tunnel1 ,great ,nor!rn ,ry4 ,! orig9al timb]+ consi/$ ( sets spac$ #d ft4 ap>t c4 to c41 ) #ab #ab 94 po/s support+ wall plates1 & a five-segm5t ar* ( #ab #ab 94 timb]s jo9$ by #a-;94 d[els4 ,! ar* 0 cov]$ ) #d-;94 lagg+1 & ! space betwe5 ?is & ! ro( 0 fill$ ) cordwood4 ,except :]e ! wid? _h be5 r$uc$ by timb]+ plac$ inside ! orig9al timb]+ to increase ! /r5g?1 ! cle> wid? 0 #af ft41 & ! cle> height #bj ft4 above ! top ( ! rail4 ,fig4 #afc %[s ! timb]+ & also ! =m ( masonry l9+ adopt$4 ,! side walls are ( concrete & ! ar* ( brick4 ,?is new masonry1 ( c\rse1 requir$ ! removal ( all ! orig9al timb]+4 ,! mann] ( do+ ?is "w is z foll[s3 ,a #g-;ft4 section1 ,a ,b1 ,fig4 #afd1 0 fir/ prep>$ by remov+ "o po/ & support+ ! ar* by /ruts1 ,s ,s4 ,aft] cle>+ away any back+1 & excavat+ = ! f\ndation ( ! side wall1 two tempor>y po/s1 ,f ,f1 7 set up1 & fa/5$ by hook bolts4 ,fig4 #adf1 ,l1 & a lagg+ 0 built to =m a mold = ! concrete4 ,sev]al ( ^! #g-;ft4 sections 7 prep>$ at a "t1 ea* two be+ sep>at$ by a #e-;ft4 section ( timb]+4 ,illu/ration3 ,section1 ) ,concrete ,c>4 ,) ,wall ,plate4 ,)\t ,wall ,plate4 ,longitud9al ,section4 ,,fig4 #afd4--;,con/ruction ( ,c5t]+ ,mullan ,tunnel4 ,! mort> c> 0 !n run along1 & en\gh mort> 7#a cem5t to #c s&7 0 run by ! *ute into ea* section to make an #h-;94 lay] ( concrete4 ,z ! c> pass$ along to ea* section1 brok5 /one 0 %ovel$ into ! la/ prec$+ section until all ! mort> 0 tak5 up4 ,! walls 7 ?us built up 9 #h-;94 lay]s1 & became h>d en\gh to support ! ar*es 9 ab\t #aj to #ad days4 ,! ar*es 7 !n all[$ to re/ on ! wall1 & ! po/s ( ! rema9+ #e-;ft4 sections 7 remov$1 & ! concrete wall built up 9 ! same way z be=e4 ,! av]age progress p] work+-day 0 #cj ft4 ( side wall1 or ab\t #de cu4 yds42 & ! av]age co/1 includ+ all "w requir$ 9 remov+ ! timb] "w1 tra9 s]vice1 lights & tools1 eng9e]+ & sup]9t5d5ce1 & int]e/ on plant1 0 #h p] cubic y>d4 ,illu/ration3 ,,fig4 #afe4--;,c5t]+ ,mullan ,tunnel4 ,! c5t]+ us$ = putt+ 9 ! brick ar*es is %[n 9 ,fig4 #afe4 ,f #c ft4 to #i ft4 ( ar* 0 put 9 at a "t1 ! l5g? dep5d+ ^u ! nature ( ! gr\nd4 ,to remove ! old timb] ar*1 "o ( ! segm5ts 0 p>tly saw$ ?r\gh2 & !n a small *>ge ( giant p[d] 0 explod$ 9 x1 ! result+ dbris1 cordwood1 rock1 etc41 be+ caught by a plat=m c> ext5d+ und]nea?4 ,f ?is c> ! dbris 0 remov$ to ano!r c>1 :i* convey$ x out ( ! tunnel4 ,! c5t] 0 !n plac$ & ! brickwork begun1 ! cem5t c> %[n 9 ,fig4 #afd be+ us$ = mix+ ! mort>4 ,! size ( ! bricks us$ 0 #b #b #i ins41 f\r r+s mak+ a #bj-;94 ar* & giv+ #a4fb cu4 yds4 ( masonry 9 ! ar* p] l94 ft4 ( tunnel4 ,! bricks 7 laid 9 r[lock bond1 two gangs1 ( ?ree bricklay]s & six help]s ea*1 lay+ ab\t #ab l94 ft4 p] day4 ,! brickwork co/ ab\t #ag p] cu4 yd4 ,! total co/ ( ! new l9+ av]ag$ ab\t #ej p] l94 ft4 ,illu/ration3 ,cross ,section4 ,longitud9al ,section4 ,,fig4 #aff4--,rel9+ ,timb]-,l9$ ,tunnel1 ,norfolk & ,we/]n ,ry4 ,little ,tom ,tunnel4--,! tunnel has a total l5g? ( #a1ijb ft41 b only #a1daj ft4 ( x 7 orig9ally l9$ ) timb]4 ,?is old timb] l9+ consi/s ( b5ts spac$ #c ft4 ap>t1 & locat$ z %[n by ! dott$ l9es 9 ! cross-section1 ,fig4 #aff4 ,in/ead ( r5ew+ ?is timb]1 x 0 decid$ to replace x ) a brick l9+4 ,al?\gh ! tunnel 0 con/ruct$ ?r\gh rock1 ?is rock is ( a seamy "*1 & 9 "s portions ( ! tunnel x dis9tegrates on exposure to ! air4 ,9 remov+ ! timb] to make place = ! new l9+ "s ( ! ro( 0 f\nd close to ! lagg+1 b (t5 also consid]able sections %[$ breakages 9 ! ro( ext5d+ to a height v>y+ f #a ft4 to #ab ft4 above ! upp] side ( ! timb]+4 ,?is dang]\s condition ( ! ro( made x necess>y t only a small section ( ! timb] l9+ %\ld be remov$ at "o "t4 ,x made x necess>y1 also1 t ! brick ar* %\ld be built quickly to close ?is op5+1 & f9ally t all details ( c5t]s1 etc41 %\ld be arrang$ s z to furni% ample cle>ance to tra9s4 ,! accompany+ illu/rations %[ ! solution ( ! problem :i* 0 arriv$ at4 ,illu/ration3 ,,fig4 #afg4--,rel9+ ,timb]-,l9$ ,tunnel1 ,norfolk & ,we/]n ,ry4 ,ref]r+ to ! transv]se & longitud9al sections %[n by ,fig4 #aff1 x w be se5 t two side tre/les 7 built to c>ry an adju/able c5t]+ = ! ro( ar*4 ,two sections ( ^! tre/les & c5t]+s 7 us$ alt]nately1 "o be+ c>ri$ ahead & set up to remove ! timb]+ :ile ! masons 7 at "w on ! o!r4 ,! mann] ( sett+ up & adju/+ ! tre/les & c5t]+s is %[n by ,fig4 #aff & also by ,fig4 #afg1 :i* is an enl>g$ detail draw+ ( ! set screw & roll]s = ! c5t]+ ribs4 ,! foll[+ is ! bill ( mat]ial requir$ = "o set ( tre/les & "o c5t]3 ,tre/les3 ,caps & sills #h pieces #h #h ins4 #bj ft4 ,po/s #ah #h #h #aa ,braces #af #f #d #g ,c5t]+s3 ,ribs #bg #b #ah #g ,brac+ #ab #b #h #g ,support to cr[n lagg+ #b #f #f #aj ,cr[n lagg+ #bj #c #f #b ,side lagg+ #cj #c #f #aj ,side /rips #b #b #ab #i ,block+ = roll]s #a #e #h #ab #f screw & roll] ca/+s complete ) bolts & lev]2 #aad bolts -ins4 9 diamet]2 #g ,u4 ,h4 hexagonal nut & #b ca/ wa%]s ea*4 ,) ?is arrangem5t ! progress made p] day v>i$ f #b l94 ft4 to #c l94 ft4 ( l9+ complete4 ,by "w complete is meant ! entire l9+1 includ+ /one pack+ betwe5 ! brickwork & ! rock4 ,on ,feb4 #bc1 #aijj1 #cfc ft4 ( l9+ _h be5 complet$1 at a co/ ( #cc4ej p] l94 ft4 ,?is co/ includes ! co/ ( remov+ ! old timb]1 ! loose rock above x1 & all o!r "w :atsoev]4 ,,*apt] ,,xxiv4 ,,! ,,v5tilation ,,& ,,light+ ,,( ,,tunnels ,,dur+ ,,con/ruction4 ,,v5tilation4 ,9 long tunnels1 especially :5 excavat$ 9 h>d rock1 prop] v5tilation is ( great importance1 because ! air _c be easily r5ew$1 & ! am\nt ( oxyg5 consum$ by m9]s horses & lamps dur+ con/ruction is v l>ge4 ,! gases produc$ by bla/+ also t5d to fill ! head ( excavation ) f\l air4 ,pure atmosph]ic air conta9s ab\t #ba ( oxyg5 & only #j4jd ( c>bonic acid2 :5 ! latt] gas rea*es #j4a ! fact is indicat$ by ! bad odor2 at #j4c ! air is consid]$ f\l1 & :5 x rea*es #j4e x is dang]\s4 ,x is g5]ally admitt$ t ! /&>d ( purity ( ! air is :5 x conta9s #j4jh ( c>bonic acid4 ,a l>ge quantity ( c>bonic acid 9 ! air is easily detect$ by obs]v+ ! lamps1 :i* !n give out a dim r$ light & smoke p]ceptibly2 ! workm5 also suff] f heada*e & pa9s 9 ! eyes1 & brea! ) difficulty4 ,naturally1 m9]s _c easily "w 9 f\l air &1 !re=e1 make v sl[ progress4 ,x is1 !re=e1 to ! int]e/ ( ! eng9e] to af=d good v5tilation1 n only because ( 8 duty to c>e = ! safety & heal? ( 8 m51 b also = reasons ( economy1 s t ! m5 may "w ) ! greate/ possible ease1 ?us assur+ ! rapid progress ( ! "w4 ,x w\ld be impossible to *ange completely ! atmosph]e inside a tunnel1 z ! gases develop$ f bla/+ w p5etrate into all ! cavities & ga!r !re1 b ! fre% air c>ri$ inside by v5tilation has a v small p]c5tage ( c>bonic acid1 mixes ) t :i* conta9s a great] quantity1 & dilutes x until ! air rea*es ! /&>d ( purity4 ,we h n "h consid]$ ! gases develop$ f ! decomposition ( c>bonif]\s & sulphuric rocks1 :i* may be met ) 9 "s tunnels1 & :i* r5d] v5tilation /ill m necess>y4 ,tunnels may be v5tilat$ ei!r by natural or artificial means4 ,natural ,v5tilation4--,x is well kn[n t if two rooms ( diff]5t temp]atures are put 9 communication ) ea* o!r1 e4g41 by op5+ a door1 a draft f ! cold] room w ent] ! o!r f ! bottom1 & a simil> draft at ! top1 b ) a contr>y direction1 w c>ry ! hot air into ! cold] room1 ?us produc+ p]fect v5tilation1 until ! two rooms h ! same temp]ature4 ,n[1 dur+ ! con/ruction ( tunnels ! temp]ature inside may be consid]$ z con/ant1 or indep5d5t ( ! outside atmosph]ic v>iations2 h5ce dur+ summ] & w9t]1 !re w always be a draft af=d+ v5tilation1 ow+ to ! diff]5ce ( temp]ature inside & outside ! tunnel4 ,9 w9t] "t ! cold air outside w ent] at ! bottom ( ! entrances & head+s1 or along ! sides ( ! %afts1 & ! hot air w pass out ne> ! top ( ! head+s or entrances or ! c5t] ( ! %afts2 9 summ] ! air curr5ts w take ! contr>y direction4 ,natural v5tilation 9 tunnels is improv$ :5 ! excavation ( ! head+ rea*es a %aft1 because ! int]ior air c !n communicate ) ! ext]ior at two po9ts1 at diff]5t levels4 ,9 su* cases a =ce equal to ! diff]5ce 9 weight betwe5 a column ( air 9 ! %aft & a simil> "o ( diff]5t d5sity at ! entrance ( ! tunnel1 w act ^u ! mass ( air 9 ! tunnel & keep x 9 movem5t1 ?us produc+ v5tilation4 ,consequ5tly1 dur+ w9t]1 :5 ! outside air has great] weight ?an t inside1 ! air w come 9 by ! head+s & g out by ! %aft1 & 9 ! summ] x w ent] at ! %aft & pass out at ! entrance4 ,sometimes to af=d bett] v5tilation %afts #h or #ab 94 9 diamet] are sunk exclusively = ! purpose ( *ang+ ! air4 ,:5 ! inside temp]ature is equal to t outside1 z (t5 happ5s dur+ ! spr+ & autumn1 !re are no drafts1 & consequ5tly ! air 9 ! excavation is n r5ew$ & becomes f\l2 !n fires are light$ "u ! %aft & a draft is artificially produc$4 ,! hot air go+ out ?r\gh ! %aft1 z ?r\gh a *imney1 all[s ! fre% air to come 9 z 9 ord9>y v5tilation4 ,:5 ! head ( ! excavation is v f> f ! entrances1 or :5 ! m\nta9 is too high to all[ excavation by %afts1 x is q impossible to secure good natural v5tilation1 especially dur+ ! spr+ & autumn mon?s1 & ! eng9e] has to resort to "s artificial means by :i* to supply fre% air to ! workm54 ,artificial ,v5tilation4--,artificial v5tilation 9 tunnels may be obta9$ 9 two diff]5t ways1 kn[n z ! vacuum & pl5um me?ods4 ,_! *>act]i/ic diff]5ce consi/s 9 ?is1 t 9 ! vacuum me?od ! air is drawn f ! inside & ! vacuum ?us produc$ causes ! fre% air f ! outside to ru% 91 :ile ! pl5um me?od consi/s 9 =c+ 9 ! fre% air :i* dilutes ! c>bonic air produc$ inside ! tunnel by work+m5 & explosives4 ,9 ! vacuum me?od ! pressure ( ! atmosph]e inside ! tunnel is always less ?an ! pressure outside1 :ile 9 ! pl5um me?od ! pressure )9 is always great] ?an t outside4 ,v5tilation is ! result ( ?is diff]5ce ( pressure1 z ! t5d5cy ( ! air t[>d equilibrium produces cont9u\s drafts4 ,bo? ^! me?ods h _! advantages & disadvantages2 b 9 ! pres5ce ( h>d rock1 :5 explosives are cont9ually requir$1 ! vacuum me?od is consid]$ ! be/1 because ! gases attract$ to ! exhau/ pipes are expell$ )\t pass+ ?r\gh ! :ole l5g? ( ! tunnel1 ?us avoid+ ! tr\ble t a draft ( f\l air w give to ! workm5 :o are )9 ! tunnel4 ,9 bo? ^! me?ods x is necess>y to sep>ate ! fre% air f ! f\l "o2 & ?is is done by means ( pipes :i* w exhau/ & expel ! f\l air 9 ! vacuum me?od1 or =ce to ! front a curr5t ( fre% air :5 ! pl5um me?od is us$4 ,artificial v5tilation may also be obta9$ by compress$ air :i* is set free aft] x has driv5 ! ma*9es1 especially 9 tunnels excavat$ ?r\gh rock1 :5 rock drill+ ma*9es mov$ by compress$ air are employ$4 ,vacuum ,me?od ,contrivances4--,! mo/ common ( ! vacuum appliances consi/s 9 ! simple arrangem5t ( a pipe lead+ f ! head ( ! tunnel out ?r\gh ! fire ( a furnace4 ,! air 9 ! pipe is r>efi$ by ! heat ( ! furnace & !n set free f ! o!r end ( ! pipe1 ?us creat+ a p>tial vacuum 9 ! pipe1 into :i* ! f\l air ( ! head ru%es1 ! fre% air f ! entrance tak+ its place1 & ?us v5tilat+ ! tunnel4 ,a simil> arrangem5t may be us$ ) %afts1 & ! f\l air may be driv5 out by a furnace :i* is plac$ ei!r at ! top or bottom ( ! %aft4 ,su* furnaces act ! same z ^? commonly us$ = heat+ purposes 9 ! h\ses1 ) ?is diff]5ce1 t1 in/ead ( fre% air be+ =c$ 91 f\l air is expell$4 ,ano!r simple arrangem5t = produc+ a vacuum is by means ( a /eam jet :i* is ?r[n into ! pipe1 & :i* helps ! expulsion ( ! air by heat+ x1 ?us produc+ a diff]5t d5sity :i* orig9ates a draft besides t me*anically orig9at$ by ! =ce ( ! /eam jet1 :i* t5ds to c>ry out ! f\l air ( ! pipes4 ,f\l air may also be expell$ by means ( exhau/ fans :i* are connect$ ) pipes ne> ! entrance ( ! tunnel4 ,! fan consi/s ( a box conta9+ a k9d ( a paddle :eel turn$ by /eam or wat] p[] & arrang$ s z to revolve at a high spe$4 ,! air inside ! pipe is =c$ out by blades atta*$ to ! :eel1 & ?us ! f\l air ( ! front is driv5 away & fre% air f ! entrance ru%es 9 to take its place1 & p]fect v5tilation is obta9$4 ,! be/ mann] ( expell+ f\l air f tunnels1 accord+ to ! vacuum me?od1 is by means ( bell exhau/]s4 ,?is consi/s ( two sets ( bells connect$ by an oscillat+ beam & balanc+ ea* o!r4 ,ea* set consi/s ( a movable bell1 :i* cov]s & surr\nds a fix$ bell ) a wat] jo9t4 ,9 ! c5tral "p ( ! fix$ bell !re are valves :i* op5 upw>ds1 & on ! bottom ( ea* movable bell !re are valves :i* op5 f ! outside4 ,:5 "o bell asc5ds1 ! valves at ! bottom are clos$1 ! air b5ea? is !n r>efi$1 & a vacuum is produc$2 ! valves 9 ! c5tral "p ( ! fix$ bell fill$ ) wat] are op5$1 & !re is an aspiratory action f ! pipe lead+ to ! head+s1 & ! f\l air is ?us c>ri$ away4 ,! app>atus makes ab\t t5 oscillations p] m9ute1 & ! dim5sions ( ! bells dep5d ^u ! quantity ( air to be exhau/$ 9 a m9ute4 ,9 ! ,/4 ,go?>d tunnel1 :]e ^! bell exhau/]s 7 us$1 !y exhau/$ #af1ejj cu4 ft4 ( air p] m9ute4 ,pl5um ,me?od ,contrivances4--,fre% air may be driv5 into tunnels to dilute ! c>bonic acid by two diff]5t ways1 viz41 by wat] bla/ & by fans4 ,wat] :5 runn+ at a great velocity produces a movem5t 9 ! air :i* may be sometimes usefully & economically employ$ = v5tilat+ tunnels4 ,wat] fall+ v]tically is let run into a l>ge horizontal z9c pipe hav+ a funnel at ! out] end2 into ?is ! air attract$ by ! velocity ( ! wat] is =c$4 ,by an op5+ at ! bottom ! wat] is aft]w>d )drawn f ! pipe1 & !re rema9s only ! air :i* is pu%$ =w>d by ! air :i* is be+ cont9ually suck$ 9 by ! velocity ( ! wat]4 ,! be/ & mo/ common means ( v5tilation by ! pl5um me?od is by fans4 ,!re are num]\s v>ieties ( ^! fans 9 ! m>ket1 b !y all consi/ ( a k9d ( fan :eel :i* by rapid revolution =ces ! fre% air into ! pipe lead+ to ! head+s ( ! tunnel or to ! work+ places4 ,in/ead ( a l>ge s+le fan1 su* z is us$ = m9+ purposes1 x is bett] to h a numb] ( small fans act+ indep5d5tly ( ea* o!r1 convey+ ! fre% air :]e x is ne$$ ?r\gh indep5d5t pipes4 ,sacc>do's ,sy/em4--,a new me?od ( v5tilat+ tunnels 0 devis$ by ,mr4 ,sacc>do = ! v5tilation ( ! ,prac*ia tunnel along ! ,bologna & ,lucca ,railway 9 ,italy4 ,at ! highe/ end ( ! tunnel ! m\? 0 contract$ inw>d 9 a funnel %ap$ =m s z to j admit a tra94 ,imm$iately at ?is contraction1 a lat]al tunnel1 #ej feet long1 bran*$ (f f "o side ( ! ma9 tunnel4 ,at ! m\? ( ?is lat]al tunnel 0 in/all$ a fan :i* =c$ air into ! tunnel & ) #gj revolutions p] m9ute deliv]$ #c4ecb cu4 ft4 ( air p] second at a wat] pressure ( #a 94 ,?is air curr5t 0 direct$ inw>d ?r\gh a second contraction or funnel1 p>allel to ! "o at ! entrance & #bc ft4 beyond x4 ,9 op]ation ! action ( ! artificial air curr5t 0 to suck 9 a consid]able volume ( outside air1 :ile ! air pressure 0 suffici5t to c\nt]balance ! movem5t ( air produc$ by a tra9 mov+ at a velocity ( #af4a ft4 p] second4 ,mr4 ,sacc>do's me?od 0 employ$ 9 v5tilat+ a tunnel on ! ,norfolk & ,we/]n ,railway ) satisfactory results4 ,compress$ ,air4--,9 ! excavation ( tunnels 9 h>d rock a numb] ( rock drill+ ma*9es are employ$ :i* are mov$ by compress$ air at a pressure ( n less ?an five atmosph]es4 ,at ea* /roke ab\t #ajj cu4 ins4 ( compress$ air are set free1 & at an av]age ( #aj /rokes p] m9ute !re w\ld be #ejjj cu4 ins4 ( air at five atmosph]es or #be1jjj cu4 ins41 or a little m ?an #age cu4 ft4 ( fre% air at normal pressure set free e m9ute by ea* ( ! ma*9es employ$4 ,b ! air exhau/$ f ! drill+ ma*9e is f\l4 ,reg>d+ v5tilation by compress$ air1 ,mr4 ,adolph ,sutro1 9 a lecture deliv]$ to ! m9+ /ud5ts ( ! ,univ]sity ( ,cali=nia1 said3 8,i w note a curi\s fact :i* ,i h nev] se5 expla9$1 & :i* is wor?y ( close inve/igation by means ( exp]im5ts4 ,9 ! ,sutro tunnel we f\nd t ! compress$ air us$ = driv+ ! ma*9e drills1 aft] hav+ be5 compress$ & exp&$ & dis*>g$ f ! drills1 0 n :olesome to brea!1 & ! m5 & mules w\ld all cr[d ar\nd ! end ( ! bl[] pipe to get fre% air4 ,:e!r ! air 9 be+ compress$ has p>t$ ) "s ( its oxyg5 or because vitiat$ f "s o!r cause1 ,i d n "k1 & ,i hope t ?is subject w at "s future day be c>efully exam9$ into40 ,9 ! ,decemb]1 #aija1 numb] ( 8,compress$ ,air10 a magaz9e especially devot$ to ! useful application ( compress$ air1 is read3 ,compress$ air wa/$ f p[] drills is s contam9at$ ) oil f ! cyl9d]s t x _c be tak5 into consid]ation z v5tilation4 ,x is z important to displace x ) pure air z x is to drive out or draw (f o!r vitiat$ air4 ,! v5tilation %\ld be an indep5d5t supply provid$ by fan or bl[]1 deliv]+ by pipe at ! po9t :]e m9]s are work+4 ,quantity ( ,air4--,! quantity ( air to be introduc$ into tunnels mu/ be 9 proportion to ! oxyg5 consum$ by ! m51 ! animals1 & ! explosions4 ,x is all[$ t ! quantity ( air requir$ = brea?+ purpose & explosions is z foll[s3 #a workman ) lamp ne$s #bdj cu4 yds4 ( fre% air 9 #bd h\rs4 #a horse #hej #a lb4 gunp[d] #ajj #a lb4 dynamite #aej ,9 a long tunnel excavat$ ?r\gh h>d rock ! numb] ( workm5 all toge!r may be assum$ at #djj at ea* end1 & ea* workman is suppos$ to be furni%$ ) a lamp4 ,no less ?an t5 horses are employ$1 & ! av]age quantity ( dynamite consum$ is #fjj lbs4 p] day4 ,f ! data giv5 ! consumption ( air by workm5 & lamps w\ld be3 #bdj #djj #if1jjj cu4 yds42 ! consumption ( air by horses w\ld be #hej #aj #hejj cu4 yds42 ! consumption ( air by dynamite w\ld be #aej #fjj #ij1jjj cu4 yds42 mak+ a total consumption ( air p] day ( #aid1ejj cu4 yds41 or ab\t #hjjj cu4 yds4 p] h\r4 ,to obta9 good v5tilation1 !n1 x w be necess>y to furni% e h\r a quantity ( fre% air am\nt+ to n less ?an #hjjj cu4 yds4 ,s9ce1 h[ev]1 a l>ge quantity ( pure air is expell$ ) ! f\l air1 x is necess>y greatly to increase ?is quantity4 ,x may be obs]v$1 9 clos+1 t ! wat] hav+ its p>ticles divid$1 z 9 a fog or mi/1 rapidly precipitates ! gases produc$ by explosions4 ,n[1 :5 hydraulic ma*9es are us$1 !re is a holl[ ball pi]c$ by holes t are almo/ imp]ceptible1 f :i* ! compress$ wat] spreads 9 v subtile p>ticles1 & ?is causes ! fall ( ! gases f explosions4 ,su* a me?od ( precipitat+ gases is v good1 b does n h ! advantage ( supply+ new oxyg5 to replace t consum$ by ! m51 animals1 lamps1 & explosions2 besides1 x has ! defect ( increas+ ! quantity ( wat] to be remov$4 ,9 tunnels ! pipes us$ ei!r = convey+ ! fre% air or = c>ry+ away ! f\l air1 are ( iron1 hav+ a diamet] ( ab\t #h 942 !y are fix$ along ! side walls ab\t #c ft4 above ! inv]t$ ar*4 ,,light+4 ,! object & necessity ( a p]fect light+ ( ! tunnel-work+s dur+ con/ruction are s obvi\s t !y ne$ n be enl>g$ ^u4 ,comp>atively few tunnels require light+ aft] completion2 & ^! are g5]ally tunnels = pass5g] traffic "u city /reets1 ( :i* ! ,bo/on ,subway is a repres5tative ,am]ican example4 ,consid]+ ! me?ods ( light+ tunnels dur+ con/ruction1 we may1 = sake ( conv5i5ce1 *iefly1 divide ! means ( supply+ light into 7#a7 lamps & lant]ns usually burn+ oil2 7#b7 coal-gas light+2 7#c7 acetyl5e gas light+2 & 7#d7 electric light+4 ,lamps & ,lant]ns4--,lamps & lant]ns are commonly employ$ by eng9e]s = mak+ surveys inside ! tunnel1 & to light ! in/rum5t4 ,= rang+ 9 ! c5t] l9e1 a conv5i5t =m ( lamp consi/s ( an oil light inclos$ 9 glass *imney cov]$ ) %eet metal1 except = a slit at ! front & back ?r\gh :i* ! light %9es1 & on :i* ! obs]v] sights 8 in/rum5t4 ,to direct ! op]ations ( 8 rodm5 ! eng9e] usually employs a lant]n1 ei!r ) :ite or color$ glass1 mu* l ! ord9>y railway tra9man's lant]n1 :i* he sw+s accord+ to "s pre>rang$ code ( signals4 ,lamps & lant]ns are us$ by ! workm5 bo? = signal+ & = light+ ! work+s4 ,= signal+ purposes r$ lant]ns are usually plac$ to d5ote ! pres5ce ( unexplod$ bla/s or o!r po9ts ( possible dang]2 & color$ or :ite lights are usually plac$ on ! front & re> ( spoil & mat]ial tra9s4 ,= light+ purposes1 two =ms ( lamps are employ$1 :i* may be some:at crudely designat$ z lamps = individual use & lamps = g5]al light+4 ,individual lamps are usually ( small size1 & burn oil2 !y may be c>ri$ 9 front ( ! m9]'s helmet1 or be fix$ to /&>ds1 :i* c be set up close to ! "w be+ done by ea* man4 ,m9]s' safety lamps %\ld be employ$ :]e !re is dang] f gas4 ,a great v>iety ( lamps = m9+ & tunnel+ purposes are on ! m>ket1 = descriptions ( :i* ! read] is ref]r$ to ! catalogues ( _! manufactur]s4 ,lamps = g5]al light+ are always ( l>g] size ?an lamps = individual use4 ,a common =m consi/s ( a cyl9d] t5 or twelve in*es 9 diamet]1 provid$ ) a hook or bail = susp5sion1 & fill$ ) b5z9e1 gasol5e1 or o!r simil> oil4 ,connect$ ) ?is cyl9d] is a pipe ( consid]able l5g? & small diamet] ?r\gh :i* ! b5z9e or gasol5e vapor runs1 & burns :5 light$ ) a brilliant flame4 ,lamps ( ?is type burn+ gasol5e 7 ext5sively employ$ 9 build+ ! ,croton ,aqu$uct tunnel4 ,v>i\s pat5t$ =ms ( lamps = burn+ coal-oil products are on ! m>ket1 = descriptions ( :i* ! manufactur]s' catalogues may be consult$4 ,coal-gas ,light+4--,a common me?od ( light+ tunnel work+s is by pip+ coal-gas into ! head+s & drifts f "s ne>by p]man5t gas plant1 or f a special gas works con/ruct$ especially = ! "w4 ,gas light+ has ! great advantage ov] lamps & lant]ns ( giv+ a light :i* is m brilliant & /eady4 ,its great objection is ! dang] ( explosion caus$ by leaks 9 ! pipes1 by breaks caus$ by fly+ fragm5ts ( rock1 & by ! c>elessness ( workm5 :o neglect to turn (f completely ! burn]s :5 !y ext+ui% ! lights4 ,9 ne>ly e tunnel :]e gas has be5 us$ = light+1 ! records ( ! "w %[ ! occurr5ce ( accid5ts :i* h sometimes be5 v s]i\s1 p>ticul>ly :5 fire has be5 communicat$ to ! tunnel timb]+4 ,acetyl5e ,gas ,light+4--,! comp>atively rec5t developm5t ( acetyl5e gas manufactur$ f c>bide ( calcium has giv5 little opportunity = its use 9 tunnel light+1 & ! only in/ance ( its use 9 ! ,unit$ ,/ates1 s f> z ! au?or kn[s1 is ! wat]-works tunnel conduit = ! city ( ,wa%+ton1 ,d4 ,c4 ,col4 ,a4 ,m4 ,mill]1 ,u4 ,s4 ,eng9e] ,corps1 :o is 9 *>ge ( ?is "w1 describes ! me?od adopt$ 9 8 annual report = #ahii z foll[s3-- 8,x _h be5 ! practice to d all "w und]gr\nd by ! light ( m9]s' lamps & tor*es4 ,?is means ( illum9ation is v poor = me*anical "w4 ,! fumes & smoke f bla/+1 add$ to ! smoke f tor*es & lamps1 r5d] ! atmosph]e und]gr\nd1 especially :5 ! b>omet] conditions 7 unfavorable to v5tilation1 v (f5sive & discom=t+ to ! workm54 ,an inve/igation ( ! subject ( light+ ! tunnel by o!r means1 m especially at ! locality :]e ! me*anics 7 at "w1--brick & /one masons1 & ! workm5 on ! iron l9+1--result$ 9 ! selection ( acetyl5e gas z ! mo/ available & economical 9 ?is special em]g5cy4 ,accord+ly1 an acetyl5e gas plant = #cjj burn]s 0 erect$ at ,*ampla9-,av5ue %aft1 & "o = #fj lights at ,f\ndry ,bran*4 ,! eng9e-h\ses at ! %afts1 ! head-h\ses1 & localities 9 ! tunnel1 :5 requir$1 are light$ by ^! plants4 8,gas pipes 7 c>ri$ d[n ! ,*ampla9-,av5ue %aft & along ! tunnel bo? 9 an ea/]ly & we/]ly direction1 ) cocks = burn]s at prop] int]vals e #cj feet2 & ?is sy/em suffic$ = illum9ation f ,hock ,creek to ,h>v>d ,univ]sity1 a di/ance ( ov] two miles4 ,! plant erect$ at ,f\ndry ,bran* 0 9 l mann] utiliz$ = ! illum9ation f t po9t 9 bo? directions4 8,by connect+ ) ! /opcocks by means ( a rubb] hose1 a movable light1 *&eli]1 or #8,*ri/mas-tree' ( any requir$ numb] ( burn]s is us$1 ?us conc5trat+ ! light 9 ! imm$iate vic9ity ( ! "w1 & also enabl+ ! illum9ation to be c>ri$ into ! cavities or #8cr[-ne/s1' s call$1 beh9d ! defective old l9+4 8,?is me?od ( illum9at+ has prov$ v satisfactory & q economical4 ,x is especially valuable z enabl+ good "w to be done1 & facilitat+ a ?or\gh inspection ( ! same40 ,electric ,light+4--,by f> ! mo/ p]fect1 & at pres5t ! mo/ commonly employ$ means = light+ tunnel work+s1 is electricity4 ,! light furni%$ by electric lamps is /eady & brilliant1 & does n consume oxyg5 or give (f (f5sive gases4 ,! wires are easily remov$ & ext5d$1 & ! lamps are easily put 9 place & remov$4 ,ab\t ! only objection to ! me?od is ! fragility ( ! lamps1 :i* are easily brok5 by ! fly+ /ones & ! concussion produc$ by bla/+4 ,,*apt] ,,xxv4 ,,! ,,co/ ,,( ,,tunnel ,,excavation ,,& ,,! ,,"t ,,requir$ ,,= ,,! ,,"w4 ,co/4--,! co/ ( a tunnel w dep5d ^u ! co/ ( ! two pr9cipal op]ations requir$ 9 its con/ruction1 viz41 ! excavation ( ! cross section & ! l9+ ( ! excavation ) masonry1 metal1 or timb]4 ,^! two op]ations may 9 turn be subdivid$1 9 respect to exp5se1 into co/ ( labor & co/ ( mat]ials4 ,x is a comp>atively simple matt] to calculate ! co/ ( ! build+ mat]ials requir$ to con/ruct a tunnel2 b x is v difficult to e/imate ) accuracy :at ! co/ ( labor w be4 ,! reason = ?is is t x is impossible to =esee exactly :at ! conditions w be2 ! "* ( ! mat]ial may *ange greatly z ! "w proce$s1 increas+ or decreas+ ! co/ ( excavation2 wat] may be enc\nt]$ 9 quantities :i* w mat]ially increase ! difficulties ( ! "w1 etc4 ,nev]!less1 :ile accurate prelim9>y e/imates ( co/ are n practicable1 x is always desirable to attempt to obta9 "s idea ( ! probable exp5se ( ! "w be=e beg9n+ x1 & ! m usual means ( gett+ at ?is po9t w be discuss$ "h4 ,two me?ods ( e/imat+ ! co/ ( tunnel "w are employ$4 ,! fir/ is to calculate ! probable exp5se ( ! v>i\s items ( "w1 bas$ ^u ! available data1 p] unit ( l5g?1 & !n add to ?is a m>g9 ( at lea/ #aj to all[ = cont+5cies2 ! second is to apply to ! new "w ! unit co/ ( "s previ\s tunnel built "u sub/antially ! same conditions4 ,9 ! fir/ me?od x is usual to consid] ! /rutt+ & haul+ z con/itut+ a "p ( ! "w ( excavation4 ,to e/imate ! co/ ( excavation involves ! consid]ation ( ?ree g5]al items1 viz41 ! excavation prop]1 ! /rutt+ ( ! walls ( ! excavation1 & ! haul+ ( ! excavat$ mat]ials & ! mat]ials ( con/ruction4 ,! co/ ( excavat+ ! prelim9>y head+s or drifts is great] p] unit ( mat]ial remov$ ?an t ( excavat+ ! enl>gem5t ( ! section4 ,! co/ ( bottom drifts is also always great] ?an t ( top head+s1 ! mat]ial p5etrat$ rema9+ ! same4 ,mr4 ,rziha gives ! comp>ative unit co/s ( excavat+ drifts1 head+s1 & enl>gem5t ( ! pr(ile z foll[s3-- ,bottom drifts #i4bj p] cu4 yd4 ,top head+s #d4hj ,enl>gem5t ( pr(ile #b4hd ,! co/ ( haul+ increases ) ! l5g? ( ! tunnel4 ,?is fact & am\nt ( ?is increase are indicat$ by ! foll[+ actual prices = ! ,arlb]g tunnel3-- ,top head+ #f4gf p] cu4 yd41 increas+ #cg cts4 p] mile ,bottom drift #g4dj #bf ,enl>gem5t ( pr(ile #b4gj #aj ,9 all ! prices giv5 above1 ! co/ ( /rutt+ & haul+ is includ$ 9 ! co/ ( excavation4 ,! co/ ( excavation is n always ! same = ! same "* ( mat]ials 9 diff]5t tunnels4 ,! foll[+ figures %[ ! prices paid = ! excavation ( calc>e\s rock 9 f\r diff]5t ,g]man tunnels3-- ,b]l9] ,nordhaus5 ,wetzl] ,r4,r4 #a4bd p] cu4 yd4 ,(5 #a4cj ,/affla* #b4gf ,gries #a4ib ,! me?od ( tunnel+ has little influ5ce ^u ! co/ ( ! "w1 z %[n by ! foll[+ figures f tunnels excavat$ ?r\gh calc>e\s rock by diff]5t me?ods3-- ,(5 tunnel ,au/rian me?od #ic4ai p] l94 ft4 ,dorremb]g tunnel ,belgian me?od #hf4jh ,/affla* tunnel ,engli% me?od #ia4fi ,! ,m>?a & ,m]t5 tunnels1 excavat$ ?r\gh s(t gr\nd by ! ,au/rian & ,g]man me?ods respectively1 co/ #hg4ie & #hg4ee p] l94 ft4 respectively4 ,9 ! excavation ( ! v>i\s sections ( ! tunnel = ! new ,croton ,aqu$uct 9 ,am]ica1 ! foll[+ prices 7 paid3-- ,excavation ( head+ #h to #aj4jj p] cu4 yd4 ,tunnel 9 s(t gr\nd #h to #i4jj ,tunnel 9 rock #g to #h4ej ,brick masonry #aj4jj ,timb] 9 place #dj p] ,m4 ft4 ,b4 ,m4 ,x is ! practice 9 ,am]ica to include ! "w ( haul+ "u excavation1 b n to include ! /rutt+1 :i* is paid = sep>ately4 ,9 "s cases only ! m>ket price ( ! timb] is paid = sep>ately1 ! co/ ( sett+ up be+ includ$ 9 ! price ( excavation4 ,! writ] pref]s ! ,european practice ( includ+ ! total co/ ( timb]+ "u excavation1 s9ce ! two op]ations are s closely connect$1 & s9ce ! contractor employs ! same timb] ov] & ov] aga94 ,kn[+ ! dim5sions ( ! sev]al memb]s ( ! /rutt+1 x is a simple1 al?\gh some:at t$i\s1 process to calculate ! total quantity requir$4 ,an idea ( ! quantity ( timb] requir$ = /rutt+ 9 s(t gr\nd may be _h f ! data giv5 on page #ee4 ,! quantity w decrease z ! cohesion ( ! mat]ial p5etrat$ increases1 until x becomes s small 9 h>d rock-tunnels z to cut v little figure 9 ! total co/4 ,! co/ ( hoi/+ excavat$ mat]ials ?r\gh %afts dep5ds ^u ! dep? f :i* x is hoi/$1 & ^u ! "* ( hoi/+ app>atus employ$4 ,! foll[+ table1 %[+ ! co/ ( hoi/+ = diff]5t lifts & by diff]5t me?ods1 is giv5 by ,rziha1 ! co/ be+ 9 francs p] cubic met]3-- ---------------------------------------- ------------ ,,height ,,w9dlass4 ,,horse ,,g9s4 ,,/eam ,,hoi/s4 ,,9 ---------------------------------------- ---- ,,metres4 ,,"o ,,horse4,,two ,,horses4 ,francs ,francs ,francs ,francs p] ,cu4 ,m4p] ,cu4 ,m4 p] ,cu4 ,m4 p] ,cu4 ,m4 ---------------------------------------- ----------- #ae #j4agb #j4jgg #j4jfb #j4jce #cj #j4bab #j4jhg #j4jgj #j4jde #de #j4beg #j4ajj #j4jhj #j4jej #fj #j4cje #j4aab #j4jib #j4jhb #ij #j4daj #j4aeb #j4aaj #j4jhg #abj #j4ece #j4aie #j4ace #j4jib #aej #j4gbb #j4bdj #j4aeg #j4aab ---------------------------------------- ----------- ,mr4 ,sj\rn1 a ,fr5* eng9e]1 :o has be5 connect$ ) ! con/ruction ( num]\s tunnels by ! ,belgian me?od :]e he 0 9 position to secure comp>ative figures1 has giv5 ! foll[+ rules = calculat+ ! co/ ( tunnels4 ,assum+ ,a to repres5t ! co/ ( excavat+ a cu4 yd4 9 ! op5 air1 ! co/ ( excavat+ ! same quantity und]gr\nd 9 driv+ head+s w be f #i ,a to #aa ,a1 & 9 enl>g+ ! pr(ile x w be ab\t #e ,a4 ,! co/ ( con/ruct+ s+le-track tunnels v>ies ) ! ?ickness ( ! l9+1 & may be calculat$ by ! foll[+ =mulas3 ,)\t l9+1 ,c #e4e ,a4 ,) ro( ar* only1 ,c #f4d #f4d ,a4 ,) l9+ #ah 94 ?ick1 ,c #i4d #g ,a4 ,) l9+ #b ft4 ?ick1 ,c #aa #h ,a4 ,9 ^! =mulas ,c is ! co/ p] cu4 yd4 ( excavation1 includ+ ! masonry4 ,= d\ble-track tunnels ! am\nts giv5 by ! above =mulas may be us$ by r$uc+ !m ab\t #g or #h4 ,! second me?od ( e/imat+ ! co/ ( tunnel "w consi/s 9 assum+ z a unit ! unit co/ ( tunnels previ\sly excavat$ "u simil> conditions4 ,mr4 ,la ,dame gives ! foll[+ unit prices = a numb] ( tunnels driv5 ?r\gh diff]5t mat]ials3 ---------------------------------------- ------------------------ ,,nature ,,( ,,soil4 ,,tunnels1 ,,excav4 ,,p] ,,co/ ,,p] ,,max4 ,,& ,,m94 ,,no4 ,,( ,,cu4 ,,yd4 ,,l94 ,,ft4 ,,p] ,,l94 ,,ft4 ---------------------------------------- ------------------------ ,granite-gneiss #ef #c4jg #c4he #ajj4 #fa4df #aij4dj ,s*i/ #ci #a4ch #a4ec #ge4db #dc4aa #gj4fh ,triassic #c 444 #ij4he #hd4ge #ic4cc ,jurassic #fi #a4bc #a4ch #gg4hf #ce4bd #aeg4b ,cretace\s #cd #j4fa #j4gg #ei4fj #bg4cg #ib4be ,t]ti>y & mod]n #ci #j4cc #j4fa #aje4hj #ea4eb #ahh4cf ---------------------------------------- ------------------------ ,9 ! foll[+ table is giv5 a li/ ( tunnels excavat$ ?r\gh diff]5t soils1 f ! mo/ compact to v loose mat]ials1 & driv5 accord+ to ! v>i\s me?ods :i* h be5 illu/rat$4 ,,d\ble-,,track ,,tunnels4 ---------------------------------------- ------------ ,,"n ,,( ,,quality ,,( ,,soil4 ,,co/ ,,p] ,,me?od ,,( ,,tunnels4 ,,l94 ,,ft4 ,,tunnel+4 ---------------------------------------- ------------ ,mt4 ,c5is ,granitic1 #bgc4gc ,drift4 ,/4 ,go?>d 444 #aic4fc ,head+4 ,/amm]i* ,granitic1 #aeg4ij ,engli%4 ,/alle ,brok5 s*i/1 #bij4eh ,au/rian4 ,bo!nfels ,dolomite1 #aae4fd ,engli%4 ,dorremb]g ,calc>e\s1 #hf4jh ,belgian4 ,/affla* ,calc>e\s1 #ia4fi ,engli%4 ,(5 ,calc>e\s1 #ic4ai ,au/rian4 ,w>?a ,grewack1 #hg4ie ,au/rian4 ,m]t9 ,grewack1 #hg4ee ,g]man4 ,s*loss ,matrei,clay s*i/1 #id4be ,engli%4 ,trietbitte ,clay & s&1 #bbi4j ,g]man4 ,canaan ,clay-slate1 #fi4ej ,wide head+4 ,*ur*-,hill ,clay ) %ells1 #agh4j 444 ,b]g5 ,no4 #a ,trap rock1 #ahb4ca 444 ---------------------------------------- ------------ ,,s+le-,,track ,,tunnels4 ---------------------------------------- ----------------- ,,"n ,,( ,,quality ,,( ,,soil4 ,,co/ ,,p] ,,me?od ,,( ,,tunnels4 ,,l94 ,,ft4 ,,tunnel+4 ---------------------------------------- ----------------- ,mt4 ,c5is ,gneiss1 #hb4bg ,head+4 ,/alletti ,granite & qu>tz1 #fb4ge ,au/rian4 ,m>e9 ,clay s*i/1 #fd4cf ,engli%4 ,welsb]g ,gravel1 #afe4jg ,au/rian4 ,sanc9a ,clay ( #a/ v>iety1#abi4dj ,belgian4 ,/>re ,clay ( #b;d v>iety1 #aia4fa ,belgian4 ,cri/9a ,clay ( #c;d v>iety1 #cjg4db ,italian4 ,burk 444 #hc4ij ,wide head+4 ,braf=d ,ridge444 #he4cc ,wide head+4 ,dunbei! ,lime/one1 #gj4dg ,wide head+4 ,f]gusson ,s&/one1 #cg4dfaf,wide head+4 ,port ,h5ry ,lime/one1 #hj4jjag,wide head+4 ,po9ts ,granite1 #gb4jjaf,wide head+4 ---------------------------------------- ----------------- #af ,are unl9$4 #ag ,l9$ ) timb]4 ,! ,habas tunnel ?r\gh quicks&1 betwe5 ,dax & ,ram\x1 ,france1 co/ #aah4ej p] l94 ft4 ,! co/ ( ! ,bo/on subway 0 #cdb4dj p] l94 ft4 ,! ,sev]n & ,m]sey tunnels1 con/ruct$ ?r\gh rock "u wat]1 co/ respectively #bjh4ch & #bfc p] l94 ft4 ,! ,fir/ ,?ames ,tunnel1 driv5 by ,brunel's %ield1 co/ #affa4ff p] l94 ft4 ,! ,hudson ,riv] & ,/4 ,clair ,riv] tunnels1 excavat$ ?r\gh s(t gr\nd by means ( %ields & compress$ air1 co/ respectively #cje & #cae p] l94 ft4 ,! ,blackwall d\ble-track tunnel "u ! ,riv] ,?ames1 :i* is ! l>ge/ tunnel ev] built by ! %ield sy/em1 co/ #fjj p] l94 ft4 ,9 mak+ e/imates ( ! co/ ( project$ tunnel "w bas$ on ! co/ ( tunnels previ\sly con/ruct$ ?r\gh simil> mat]ials1 x is important to keep 9 m9d ! date & location ( ! "w us$ z ! basis = calculations4 ,= example1 a tunnel excavat$ 9 ,italy1 :]e labor is v *eap1 w co/ less ?an "o excavat$ 9 ,am]ica1 :]e labor is de>1 all o!r conditions be+ ! same4 ,o!r reasons = v>iation 9 co/ due to diff]5ce ( date & location ( con/ruction w sugge/ !mselves1 & %\ld be tak5 into full consid]ation 9 e/imat+ ! co/ ( ! new "w4 ,"t4--,! "t requir$ to excavate a tunnel dep5ds ^u ! "* ( ! mat]ial p5etrat$ & ^u ! me?od ( "w adopt$4 ,tunnels driv5 ?r\gh s(t gr\nd by h& require ab\t ! same "t to con/ruct z tunnels driv5 ?r\gh h>d rock by ! aid ( ma*9]y4 ,tunnels c be driv5 ?r\gh h>d rock at ab\t z great a spe$ z ?r\gh s(t or fissur$ rock1 *iefly because ! "w ( bla/+ is m effici5t 9 h>d rock1 & because no "t is requir$ 9 timb]+4 ,! foll[+ table %[s ! av]age rate ( progress 9 diff]5t p>ts ( ! tunnel excavation ?r\gh bo? h>d & s(t mat]ials 9 feet p] mon?3-- ---------------------------------------- -------------------------- ,,quality ,,head+4 ,,excavation ,,enl>gem5t ,,( ,,soil4 ,,( ,,%afts4 ,,( ,,pr(ile4 ---------------------------------------- --------- ,by h&4 ,by ,by h&4 ,by ,by h&4 ma*9e4 ma*9e4 ---------------------------------------- ------------------------ ,v loose soil#af4g- #bf4h #f4f-af4g #f4f- #af4g ,loose soil #cc4d-ajj #af4g-cc4d #af4g- #cc4d ,s(t rock #ff4h #bcc4h-ccdcc4d-ff4hff4h-acb4f #cc4d- #ej ,h>d rock #ej - #ff4hbcc4h-ccdcc4d-ej #ff4h-acb4f #ff4h-ajj ,v h>d rock #cc4d #bcc4h-ccdaf4g-cc4dff4h-acb4f #ff4h-ajj ---------------------------------------- ------------------------ ,! foll[+ tables %[+ ! av]age rate ( progress h be5 compil$ f ! actual records made 9 ! tunnels nam$3 ---------------------------------------- --------------------- ,,"n ,,( ,,dim5sions ,,mon?ly ,,"* ,,( ,,obs]vations4 ,,tunnel4 ,,9 ,,feet4 ,,progress ,,mat]ial4 ,,9 ,,feet4 ---------------------------------------- --------------------- ,excavation ( head+s by h&3 ,m\nt ,c5is #aj #aj #fe4h ,s*i/1 ,bottom drift4 ,sutro #f4g #e4g #gj4ad ,qu>tzose1 444 ,/4 ,go?>d #h4d #h4g #gj4ad ,granite1 ,top head+4 ,excavation ( head+s by ma*9e3 ,m\nt ,c5is #aj #aj #ahh4g ,calc>e\s s*i/1 ,bottom drift4 ,sutro #h4ae #aj #bbg4de ,qu>tzose1 444 ,/4 ,go?>d #h4d #h4g #cci4de ,granite1 ,top head+4 ,tr>i #h #i4ce #afg ,gneiss1 ,top head+4 ,arlb]g #h4ce #i4ce #dgd4b ,mica s*i/1 ,bottom drift4 ,palisades #af #g #afj ,trap rock1 ,top head+4 ,busk #ae #g #abf ,granite1 ,top head+4 ,cascade #af #h #ahj ,basaltic rock1,top head+4 ,frankl9 #ae #g #bdj 444 ,top head+4 ---------------------------------------- --------------------- ,! foll[+ table %[s ! mon?ly progress ( complet$ tunnel 9 feet excavat$ ?r\gh rock3 ---------------------------------------- ----- ,,"n ,,( ,,tunnel4,,progress,,mat]ial4 ,,me?od4 ,,9 ,,feet4 ---------------------------------------- ----- ,cascade #bjg ,basalt1 ,top head+4 ,palisades #ahf ,trap rock1,top head+4 ,busk #aij ,granite1 ,top head+4 ,t5nessee ,pass #afi4e ,granite1 ,top head+4 ---------------------------------------- ----- ,! av]age mon?ly progress 9 feet ( excavat+ tunnels ?r\gh trea*]\s gr\nd may be q g5]ally assum$ to be =3 7#a7 clay ( ! fir/ v>iety f #dc4d ft4 to #fj ft42 = clay ( ! second v>iety f #cc4d ft4 to #dc4d ft42 = clay ( ! ?ird v>iety f #bc4c ft4 to #cc4d ft41 & = quicks& f #cj ft4 to #ej ft4 ,! mon?ly progress 9 feet made 9 s9k+ ! %afts ( ! ,hoosac & ,musconetcong tunnels 9 ,am]ica 0 z foll[s3-- ---------------------------------------- ---------------- ,,"n ,,( ,,tunnel4 ,,dim5sions ,,dep? ,,progress,,"* ,,( ,,9 ,,feet4 ,,9 ,,feet4 ,,9 ,,feet4 ,,mat]ial4 ---------------------------------------- ---------------- ,hoosac3 ,ea/ %aft #ae4d #bg4g #ajce #ba4g ,mica s*i/4 ,we/ %aft #h #af #bfg #af4g ,gneiss4 ,musconetcong3 ,v]tical %aft #h4ce #af4g #aac4e #ajj ,loose rock4 ,incl9$ %aft #h4ce #bf #cjd4 #cb ,loose rock4 ---------------------------------------- ---------------- ,! av]age mon?ly progress ( s9k+ %afts 9 trea*]\s soils may be assum$ to be z foll[s3 clay ( fir/ v>iety1 #ej ft4 to #ge ft2 clay ( second v>iety1 #cf4ge to #ej ft2 clay ( ?ird v>iety1 #bc4d ft4 to #cf4ge ft2 quicks&1 #af4g ft4 to #cc4d ft4 ,= ! reason t ! details *ange ) ! v>i\s conditions enc\nt]$ 9 e "w1 all ! tunnel op]ations h be5 treat$ 9 a g5]al way1 purposely avoid+ to give any detail4 ,also ! rate ( progress & items ( co/ ( tunnels h be5 giv5 9 a broad mann] because !y greatly v>y 9 ! diff]5t works4 ,?is in=mation1 h[ev]1 c be easily obta9$ by consult+ ! ,eng9e]+ ,magaz9es1 :]e are report$ all ! tunnel works ( ,am]ica & ,europe1 & :]e are giv5 s _m details :i* are v valuable to exp]t eng9e]s 9 *>ge ( simil> works1 b n to /ud5ts & p :o are look+ only = g5]al k4 ,,index ,accid5ts & ,repairs 9 ! ,belgian ,me?od1 #aeb ,accid5ts 9 ,tunnels3 ,aft] ,con/ruction1 #cjh ,baltimore ,belt ,l9e1 #afe ,*attanooga ,tunnel1 #caa ,dur+ ,con/ruction1 #cja ,g5]al ,discussion1 #cja ,giovi ,tunnel1 #cji ,repair+ (1 #cjd ,acetyl5e ,gas ,light+1 #ccd ,air ,compressors1 ,description (1 #hg ,air ,locks1 #bfd-bgb ,air ,pressure1 #bfh ,am]ican ,me?od3 ,g5]al ,description1 #agb ,excavation1 #agb ,/rutt+1 #agd ,haul+1 #age ,arrangem5t ( ,drill ,holes1 #ij ,artificial ,v5tilation1 #cbg ,au/rian ,me?od ( ,tunnel+3 ,advantages & ,disadvantages1 #ahj ,excavation1 #agf ,g5]al ,description1 #agf ,l9+1 #ahj ,/rutt+1 #agg ,av]age ,progress 9 ,tunnels1 #cdb ,baltimore ,belt ,l9e ,tunnel1 ,g5]al ,description1 #afj ,b>l['s ,%ield1 #bdb ,bea*'s ,%ield1 #bdf ,belgian ,me?od3 ,accid5ts & ,repairs1 #aeb ,advantages & ,disadvantages1 #aeb ,excavation1 #ade ,g5]al ,description1 #add ,l9+1 #adh ,haul+1 #aej ,/rutt+1 #adf ,b5*1 #aca ,b5ds1 #bfh ,blackwall's ,tunnel ,%ield1 #bdh ,bla/+-cone1 #cc ,blick=d ,mat*1 #ca ,bo/on ,subway3 ,g5]al ,descriptions1 #bjc ,ro( ,%ield1 #bea ,b\ld] ,tunnel ,rel9$1 #cae ,box-c>s1 #fa ,box ,/rutt+1 #ea ,br&t ,drill+ ,ma*9e1 #bh1 #aab ,br[n1 ,w4 ,l41 #bfi ,brunel's ,%ield1 #bdj ,caissons1 #bic ,canals & ,pipe ,l9es1 #hf ,cascade ,tunnel1 #ih ,c5t]-cut1 #ia ,c5t] ,l9e3 ,curvil9e> ,tunnels1 #ad ,det]m9ation (1 #i ,rectil9e> ,tunnels1 #i ,simplon ,tunnel1 #ajf ,subm>9e ,tunnels1 #bfe ,triangulation1 #ab ,transf]r$ ?r\gh ,c5t] ,%afts1 #ac ,transf]r$ ?r\gh ,side ,%afts1 #ad ,value's ,device1 #aj ,c5t]s3 ,= ,ar*es1 #fh ,engli% ,me?od1 #afi ,gr\nd ,molds1 #ff ,italian ,me?od1 #ahd ,lagg+1 #ga ,lead+ ,frames1 #fg ,sett+ ,up1 #gj ,/rik+1 #ga ,*attanooga ,tunnel1 ,accid5t1 #caa ,city & ,s\? ,london ,railway ,%ield1 #bej ,classification ( ,tunnels1 #db ,coal-gas ,light+1 #ccc ,c(f]dam ,me?od ( ,tunnel+1 #bha ,van ,bur5 ,/reet ,tunnel1 ,*icago1 #bhb ,collapse ( ,tunnels1 #cjb ,compress$ ,air3 ,= ,p[]1 #hg ,= ,v5tilation1 #ccj ,concrete ,l9+1 #ge ,=t ,george ,tunnel1 #aci ,murray ,hill ,tunnel1 #abf ,co/ (3 ,d\ble-track ,tunnels1 #cdj ,haul+1 #cch ,head+s1 #ccg ,hoi/+1 #cch ,s+le-track ,tunnel1 #cdj ,subm>9e ,tunnels1 #cda ,subways1 #bji-bag ,tunnels1 #ccf ,crav51 ,alfr$1 #ci ,crav5's ,sunfl[]1 #ci ,cross-section3 ,dim5sions (1 #bj ,=m (1 #ah ,hudson ,riv] ,tunnel ,p5nsylvania ,railroad1 #bgg ,cr[n-b> 7see ,am]ican ,me?od74 ,subways1 #bjd-baa ,croton ,aqu$uct ,tunnel1 #ie ,culv]ts1 #hj ,detroit ,riv] ,tunnel1 #bif ,diamond ,drill+ ,ma*9e1 #bg ,direct+ ! ,%ield1 #bfe ,drift1 #cg ,drift ,me?od3 ,g5]al ,discussion1 #ajb ,murray ,hill ,tunnel1 #abc ,simplon ,tunnel1 #ajc ,drill+ ,ma*9es3 ,br&t1 #aab ,+]soll1 #bf ,drills3 ,diamond1 #bg ,h&1 #bc ,m\nt+s =1 #be ,p]cussion1 #bd ,p[]1 #bd ,rot>y1 #bg ,dump+ ,c>s1 #fj ,electric ,fir+1 #cb ,electric ,light+1 #cce ,engli% ,me?od3 ,advantages & ,disadvantages1 #aga ,c5t]s1 #afi ,excavation1 #aff ,g5]al ,discussion1 #aff ,l9+1 #agj ,/rutt+1 #afg ,enl>gem5t ( ! ,pr(ile1 #ch ,entrances1 #ha ,erector1 #bgb ,excavation3 ,am]ican ,me?od1 #agb ,arrangem5t ( ,drill ,holes1 #ij ,au/rian ,me?od1 #agf ,belgian ,me?od1 #ade ,c5t]-cut1 #ia ,enl>gem5t ( ,pr(ile1 #ch ,engli% ,me?od1 #aff ,=t ,george ,tunnel1 #acf ,g]man ,me?od1 #aee ,head+s1 #cg1 #ia ,hudson ,riv] ,tunnel ( ,p5nsylvania ,railroad1 #bgc ,italian ,me?od1 #ahb ,murray ,hill ,tunnel1 #abd ,quicks& ,me?od1 #ahi ,pilot ,me?od1 #aic ,%ield & ,compress$ ,air ,me?od1 #bfg ,simplon ,tunnel1 #aaj ,excavat+ ,ma*9es3 ,= ,e>?1 #bb ,= ,rock1 #bc ,explosions1 #cc ,dynamite1 #cj ,gunp[d]1 #bh ,nitroglyc]9e1 #bi ,quantity (1 #cd ,/orage (1 #cj ,failure ( ,tunnel ,ro(1 #cje ,=gie1 ,james1 #bfi ,=t ,george ,tunnel1 #ace ,f\ndations = ,l9+1 #gf ,fox1 ,*>les ,b41 #ajc ,frame ,/rutt+1 #di ,fuses1 #ca ,geological ,survey1 #c ,g]man ,me?od3 ,advantages & ,disadvantages1 #aei ,excavation1 #aee ,g5]al ,description1 #aee ,haul+1 #aeh ,/rutt+1 #aef ,giovi ,tunnel ,accid5t1 #cji ,graveholz ,tunnel1 #ih ,grea!ad's ,%ield1 #bde ,h& ,drills1 #bc ,h>lem ,riv] ,tunnel1 #bhe ,haul+3 ,am]ican ,me?od1 #age ,belgian ,me?od1 #aej ,italian ,me?od1 #ahe ,g]man ,me?od1 #aeh ,hudson ,riv] ,tunnel ( ,p5nsylvania ,railroad1 #bgh ,motive ,p[]1 #fa ,by ,way ( ,entrances1 #ei ,simplon ,tunnel1 #aaa ,by ,way ( ,%afts1 #fb ,head+ & ,b5* ,me?od3 ,=t ,george ,tunnel1 #ace ,g5]al ,discussion1 #acj ,/4 ,go?>d ,tunnel1 #a ,head+s1 #cg1 #ia ,hewett1 ,h4 ,b41 #bfi ,hi/ory ( ,tunnels1 xiii ,hoi/+ ,ma*9es3 ,g5]al ,discussion1 #fb ,elevators1 #fd ,horse ,g9s1 #fc ,w9dlass1 #fc ,hoosac ,tunnel1 #ic ,hopk9s1 ,/eph5 ,w41 #ace ,hudson ,riv] ,tunnel ( ,p5nsylvania ,railroad1 #bfi ,hydraulic ,jacks1 #bfj1 #bga ,hydraulic ,rams1 #bga ,illum9ation3 ,acetyl5e ,gas1 #ccd ,coal-gas1 #ccc ,electric1 #cce ,hudson ,riv] ,tunnel ( ,p5nsylvania ,railroad1 #bhj ,lamps & ,lant]ns1 #ccj ,incl9ation ( ,/rata1 #f ,+]soll ,drill+ ,ma*9e1 #bf ,inv]t$ ,ar* ,l9+1 #gg ,iron & ,masonry ,l9+1 #gd ,iron ,l9+1 #gc1 #bfa1 #bgf ,iron ,/rutt+1 #ee ,full ,section1 #ef ,head+s1 #ef ,%afts1 #eg ,italian ,me?od3 ,advantages & ,disadvantages1 #ahh ,excavation1 #ahb ,g5]al ,description1 #ahb ,modifications1 #ahf ,/rutt+1 #ahc ,jacks1 #bfj1 #bga ,jo9+ ! ,caissons1 #bie ,lagg+1 #ga ,lamps & ,lant]ns1 #ccj ,light+ 7see ,illum9ation74 ,l9+3 ,au/rian ,me?od1 #ahj ,belgian ,me?od1 #adh ,concrete1 #abf1 #aci ,engli% ,me?od1 #agj ,f\ndations1 #gf ,g5]al ,obs]vations1 #gh ,g]man ,me?od1 #aeh ,hudson ,riv] ,tunnel ,p5nsylvania ,railroad1 #bgf ,inv]t1 #gg ,iron1 #gc1 #bfa1 #bgf ,iron & ,masonry1 #gd ,italian ,me?od1 #ahe ,masonry1 #gd ,quicks& ,me?od1 #aia ,ro( ,ar*1 #gg ,side ,tunnels1 #gi1 #hc ,side ,walls1 #gg ,subways1 #bjg-bac ,timb]1 #gb ,?ickness ( ,masonry1 #gh1 #hc ,little ,tom ,tunnel ,rel9$1 #cba ,loose ,soil 7see ,s(t ,gr\nd74 ,masonry 7see ,c5t]s74 ,masonry ,culv]ts1 #hj ,masonry 7see ,l9+74 ,masonry ,l9+1 #gd ,masonry ,ni*es1 #ha ,mc,bean1 ,daniel1 #bhe ,me*anical ,in/allations = ,tunnel ,"w1 #hd ,milwaukee ,tunnel1 #bbf ,mont ,c5is ,tunnel1 #ib ,mon?ly ,progress ( ,tunnels1 #cdb ,mullan ,tunnel ,rel9$1 #cai ,murray ,hill ,tunnel1 #abc ,natural ,v5tilation1 #cbf ,new ,york ,rapid ,transit ,subway1 #bji ,niag>a ,falls ,p[] ,tunnel1 #ig ,ni*es1 #ha ,op5 ,cut or ,tunnel1 #a ,op5-cut ,tunnel+3 ,g5]al ,discussion1 #aie ,p>allel ,longitud9al ,tr5*es1 #aig ,s+le ,tr5*1 #aif ,s+le ,n>r[ ,tr5*1 #aig ,transv]se ,tr5*es1 #bjj ,tunnels on ! ,surface1 #bjj ,palisade ,tunnel1 #id ,p5nsylvania ,railroad ,%ield1 #bgj ,p]cussion ,drills1 #bd ,pilot ,me?od ( ,tunnel+1 #aib ,plank ,c5t]s1 #fi ,plat=m ,c>s1 #ei ,pl5um ,me?od ( ,v5tilation1 #cbi ,pneumatic ,caissons1 #bhg ,pol> ,protractor1 #ci ,portals1 #ha ,p[] ,drills1 #bd ,p[] ,plants3 ,air ,compressors1 #hg ,canals & ,pipe ,l9es1 #hf ,cascade ,tunnel1 #ih ,croton ,aqu$uct ,tunnel1 #ie ,g5]al ,description1 #hd ,graveholz ,tunnel1 #ih ,hoosac ,tunnel1 #ic ,hudson ,riv] ,tunnel ,p5nsylvania ,railroad1 #bgi ,mont ,c5is ,tunnel1 #ib ,murray ,hill ,tunnel1 #abh ,niag>a ,falls ,p[] ,tunnel1 #ig ,palisades ,tunnel1 #id ,receiv]s1 #hi ,res]voirs1 #hf ,simplon ,tunnel1 #aag ,sonn/e9 ,tunnel1 #ii ,/4 ,clair ,riv] ,tunnel1 #ii ,/4 ,go?>d ,tunnel1 #acc ,/eam1 #he ,/rickl] ,tunnel1 #if ,turb9es1 #hf ,prel9i's ,%ield1 #bea ,pres5ce ( ,wat]1 #g ,prev5tion ( ,collapse1 #cjc ,progress 9 ,s9k+ ,%afts1 #cdc ,progress ( ,excavation1 #cdb ,progress ( ! ,"w1 #cdb ,progress 9 ,simplon ,tunnel1 #abb ,quantity ( ,air = ,v5tilation1 #cca ,quicks& ,tunnel+3 ,g5]al ,discussion1 #ahh ,remov+ ! ,seepage ,wat]1 #aia ,quantity ( ,timb] 9 ,/rutt+1 #ed ,receiv]s1 #hi ,rel9+ ,tunnels1 #cae ,b\ld] ,tunnel1 #cae ,little ,tom ,tunnel1 #cba ,mullan ,tunnel1 #cai ,repair+ ( ,accid5ts 9 ,tunnels1 #cjh ,res]voirs1 #hf ,ro( ,ar* ,l9+1 #gg ,ro( ,%ield = ,bo/on ,subway1 #bea ,ro( ( ,caissons1 #bhg-bia ,rot>y ,drills1 #bg ,ryd]1 ,b4 ,h41 #bif ,sacc>do ,sy/em ( ,v5tilation1 #ccj ,saund]s1 ,w4 ,l41 #hh ,seepage ,wat]1 #aia ,se9e ,riv] ,tunnel1 #bic ,sett+ up ,c5t]s1 #gj ,sev]n ,tunnel1 #bba ,%afts1 ,description (1 #dj ,%al]1 ,ira ,a41 #adb ,%ield & ,compress$ ,air ,me?od1 #bfc ,%ield ,con/ruction3 ,diaphragm1 #bef ,cellul> ,division1 #bee ,dim5sions ( ,%ields1 #bei ,front ,end1 #bed ,g5]al ,=m1 #beb ,re> ,end1 #beg ,%ell1 #bec ,%ield ,me?od3 ,b>l[ ,%ield1 #bdb ,bea*'s ,%ield1 #bde ,blackwall ,tunnel ,%ield1 #bdh ,brunel ,%ield1 #bdj ,city & ,s\? ,london ,railway ,%ield1 #bej ,grea!ad's ,%ield1 #bde ,hi/ory1 #bch ,prel9i's ,%ield1 #bea ,/4 ,clair ,riv] ,tunnel ,%ield1 #bdg ,side ,%afts1 #da ,side ,tunnels ,l9+1 #gi ,side ,walls ,l9+1 #gg ,simplon ,tunnel1 #ajc ,soils ,enc\nt]$ 9 ,tunnels1 #c ,sonn/e9 ,tunnel1 #ii ,/ations ( ,subways1 #bjg-baf ,/4 ,clair ,riv] ,tunnel ,%ield1 #bdg ,/4 ,go?>d ,tunnel1 #acb ,/eam ,p[] ,plant1 #he ,/ratification ( ! ,soils1 #f ,/rickl] ,tunnel1 #if ,/rik+ ! ,c5t]s1 #ga ,/rutt+3 ,am]ican ,me?od1 #agd ,au/rian ,me?od1 #agg ,belgian ,me?od1 #adf ,dim5sions ( ,timb]1 #ed ,engli% ,me?od1 #afg ,=t ,george ,tunnel1 #acg ,full ,section1 #ea ,g]man ,me?od1 #aef ,head+s1 #dh ,italian ,me?od1 #ahc ,murray ,hill ,tunnel1 #abe ,pilot ,me?od1 #aic ,quantity ( ,timb]1 #ed ,%afts1 #eb ,iron3 ,full ,section1 #ef ,head+s1 #ef ,%afts1 #eg ,subm>9e ,tunnel+3 ,c(f]dam ,me?od1 #bha ,compress$ ,air ,me?od1 #bbe ,detroit ,riv] ,tunnel1 #bif ,g5]al ,discussion1 #bah ,h>lem ,riv] ,tunnel1 #bhe ,hudson ,riv] ,tunnel ,p5nsylvania ,railroad1 #bfi ,l9+1 #bfa ,milwaukee ,wat]-,works ,tunnel1 #bbf ,pneumatic ,caisson ,me?od1 #bhd ,se9e ,riv] ,tunnel1 #bic ,sev]n ,tunnel1 #bba ,%ield & ,compress$ ,air ,me?od1 #bfc ,%ield ,sy/em1 #bch ,s9k+ & ,jo9+ ,sections ,built on ,l&1 #bic ,van ,bur5 ,/reet ,tunnel1 #bhb ,subways3 ,bo/on1 #bjc ,co/ (1 #bji-bag ,cross-sections1 #bjd-baa ,g5]al ,discussion1 #aie-bjb ,l9+1 #bjg-bac ,new ,york ,rapid ,transit ,railway1 #bji ,/ations1 #bjg-baf ,sutro1 ,adolph1 #ccj ,tamp+1 #cb ,?ickness ( ,l9+ ,masonry1 #gh1 #hc ,?omson ,excavat+ ,ma*9e1 #bb ,timb] ,l9+1 #gb ,timb]+ 7see ,/rutt+74 ,tremies1 #bii ,truss$ ,c5t]s1 #gj ,tunnel or ,op5 ,cut1 #a ,tunnels3 ,baltimore ,belt ,l9e1 #afj ,classification (1 #db ,=t ,george1 #ace ,murray ,hill1 #abc ,simplon1 #ajc ,/4 ,go?>d1 #acb ,h>d ,rock1 #hd ,drift ,me?od1 #ajb ,comp>ison ( ,me?ods1 #ada ,head+ & ,b5* ,me?od1 #aeb ,head+ ,me?od1 #acj ,s(t ,gr\nd3 ,am]ican ,me?od1 #agb ,au/rian ,me?od1 #agf ,belgian ,me?od1 #add ,engli% ,me?od1 #aff ,g]man ,me?od1 #aee ,italian ,me?od1 #ahb ,pilot ,me?od1 #aib ,quicks& ,me?od1 #ahh ,subm>9e3 ,detroit ,riv] ,tunnel1 #bif ,h>lem ,riv] ,tunnel1 #bhe ,hudson ,riv] ,tunnel ( ,p5nsylvania ,railroad1 #bfi ,milwaukee ,tunnel1 #bbf ,se9e ,riv] ,tunnel1 #bic ,sev]n ,tunnel1 #bba ,van ,bur5 ,/reet ,tunnel1 ,*icago1 #bhb ,"u ,city ,/reets3 ,g5]al ,description1 #bja ,bo/on ,subway1 #bjc ,turb9es1 #hf ,vacuum ,me?od ( ,v5tilation1 #cbh ,value1 ,bev]ley ,r41 #aj ,van ,bur5 ,/reet ,tunnel1 #bhb ,v5tilation1 #cbe ,artificial1 #cbg ,compress$ ,air1 #ccj ,natural1 #cbf ,pl5um ,me?od1 #cbi ,quantity ( ,air1 #cca ,sacc>do's ,sy/em1 #ccj ,simplon ,tunnel1 #abj ,vacuum ,me?od1 #cbh ,v]non-,h>c\rt1 ,l4 ,f41 #bba ,work+ ,plat=ms1 #bhf ,wyman1 ,era/us1 #bic ,transcrib]'s ,notes ,inconsi/5cies 9 spell+ & hyph5ation h be5 reta9$ except z m5tion$ bel[2 non-,engli% words & phrases h n be5 correct$ except z li/$ bel[4 ,! 7m9or7 diff]5ces betwe5 ! ,table ( ,cont5ts & ! *apt] head+s h n be5 rectifi$4 ,page #cf_/acb3 ,figs4 #ad & #fa are id5tical4 ,page #ib_/ic1 ,sommeili]3 possibly an error = ,sommeill]4 ,page #acd1 ,s\mmeli]3 possibly an error = ,sommeill]4 ,page #agd1 ,footnote #aa3 presumably ,fig4 #ib1 indicat+ ! planes ( ! sections1 is f ! same publication4 ,page #agf1 ,au/rian me?od3 ,dresd5 & ,leipsic1 & ! ,ob]au ,tunnel1 are 7& 7 9 #ahcg7 9 ,saxony1 ,g]many 7or ,prussia74 ,page #agi1 ,! %ort transv]se beam c1 ,fig4 #ij3 !re is no %ort transv]se beam visible 9 ,fig4 #ij1 nor is x cle> :i* o!r figure might be int5d$2 !re is !re=e no hyp]l9k to ! illu/ration4 ,page #bgi1 ,/irtl+ boil]3 possibly an error = ,/irl+ boil]4 ,pages #ccg & #cdb1 ,arlb]g3 possibly an error = ,a>lb]g4 ,page #cdj1 ,w>?a3 possibly an error = ,m>?a2 ,m]t93 possibly an error = ,m]t54 ,*anges made ,footnotes1 tables & illu/rations h be5 mov$ out ( text p>agraphs2 "s table data h be5 re-arrang$ = bett] legibility4 ,9 "s ( ! =mulas brackets h be5 add$ = cl>ity4 ,sev]al obvi\s m9or typographical & punctuation errors h be5 correct$ sil5tly4 ,page #ab1 footnote #c3 ,*apt] ,,ix4 *ang$ to ,*apt] ,x4 ,page #ce3 on page #aee *ang$ to on page #ace ,page #cf3 on page #cd *ang$ to on page #ce ,page #ec3 ,! lagg+ plank may be 444 *ang$ to ,! lagg+ planks may be 444 ,page #aac3 7#a7 *ang$ to 7,i7 7#b7 ,page #aag3 444 & x 9 ?is cle>+ 444 *ang$ to 444 & x is 9 ?is cle>+ 444 ,page #acj3 z indicat$ by ,fig4 #eh *ang$ to z indicat$ by ,fig4 #fa ,page #acf3 z indicat$ 9 ! ,fig4 #fc *ang$ to z indicat$ 9 ! ,fig4 #fe ,page #adf3 z %[n by ,fig4 #fc *ang$ to z %[n by ,fig4 #fi ,page #adi3 und]p9+ *ang$ to und]p9n+ ,page #aej3 ,s9ce ! ro( ar* re/s = "s "t 444 *ang$ to ,s9ce ! ro( ar* re/s are = "s "t 4442 z %[n by ,fig4 #ff *ang$ to z %[n by ,fig4 #gb ,page #agb3 illu/rat$ 9 ,fig4 #ab *ang$ to illu/rat$ 9 ,fig4 #aa ,page #age3 page #abg *ang$ to page #abc ,page #agi3 z at b1 ,fig4 #ij *ang$ to z at b1 ,fig4 #ig ,page #bjd3 ,! ?ird type ( section is %[n by ,fig4 #aaf *ang$ to ,! ?ird type ( section is %[n by ,fig4 #aag ,page #bah3 ,mal9 *ang$ to ,malm ,page #bfa3 ,fig4 #aah %[s ! hydraulic jacks *ang$ to ,fig4 #acf %[s ! hydraulic jacks ,page #bhb3 %[n by ,fig4 #aai *ang$ to %[n by ,fig4 #ada ,page #big3 t[$ d[n to ! tunnel side *ang$ to t[$ d[n to ! tunnel site ,page #cae3 %[n 9 ,figs4 #ada & #adb *ang$ to %[n 9 ,figs4 #aei & #afj ,page #cbd3 %[n by ,fig4 #adh *ang$ to %[n by ,fig4 #aff ,page #cch3 giv5 on page #ej *ang$ to giv5 on page #ee ,page #cdj3 ,scloss ,matrei *ang$ to ,s*loss ,matrei ,page #cda3 ,"t4 *ang$ to ,"t4 ,page #cdh1 entry ,ryd]3 page numb] #bif add$2 ,s\n/e9 *ang$ to ,sonn/e9 7#b74