解说词小字.docx
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解说词小字.docx
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解说词小字
Part1
Infrastructureisthedomainofthecivilengineer.Itiscivilengineerswhodesign,buildandmaintainthepublicworkswhichconstitutethephysicalframeworkofthecivilizationweenjoyandoftentakeforgranted.Inthecourseofthe20thcentury,wehaveseenachievementsinthisfieldthatourancestorcouldneverhaveimagined.
Asthemomentumofourtechnicalsuccesscarriesusforwardintothe21stcentury,itistimetoreviewwherewehavecomefrom,whatwehavelearnedandwherewearegoing.
TheAlpsloomlikesnowcappedgiants,barringthewaytotravelersbetweentheItalianpeninsulaandworldtothenorth.ThesemountainsandroofofEuropearetypicalofthechallengeswhichcivilengineeringwascreatedtoovercome.
TheworldfirstmodernmountaintunnelcametobeatHouatSuaiPark.Bornintherailwaybuildingfrenzy,itsprangfromtheindustryrevolution.DynamiteandrockdrillsusedintheAlpsinthe19thcenturylaunchedaneweraintheartoftunnelmaking.Today,theStGothard,theworldlongesthighwaytunnelruns16kmthroughtheSwissAlps.Theevolutionofthetunneltechnologyfromthe19thcenturytothepresenthasnotbeeneasy.Inmid20thcenturyJapan,theKan-montunnelandotherswerebuiltbywhatwasatthetimethemostuptodatetechnology,buttheoperationwasstilllabor-intensiveplaguedbyfloodandtheeverpresentdangerofcollapse.KlayorateScuffoldsweredesignedtokeepthegroundinplace.Structuresofwoodandsteelcanonlyprovidesupportatcertainpoints,buttroublemaybeginatanypoint.Rockistypicallyfragment,andthecracksareoftenfilledwithsandandclay.Undertheinfluenceofgravityandseepage,thisworkloose.Apieceofrockfallsout,andthenanother.Disintegrationisunderway.
In1940,anAustriantunnelengineerRabcwiczbecameknownforanewidea.TheprincipleofthenewAustriantunnelingmethod,orNATMwastotransformofthefracturedsurfaceofthetunnelintoacontinuousself-supportingarch.Wetconcreteissprayedovereveryinchofthewallsandceilingofthetunnel.Theconcreteliningpreventstheescapeofthebitsandpieceswhichifthey’rekepttogethergivethearchitsnaturalstrength.Theconcretefingersofliningreachintothecavityunitingtherockandconcreteinasinglepurpose.Successfultechnologiesspreadrapidlyinashrinkingworld,andwidespreaduseimprovesthem.
Japanislargelymountainous.Tunnelsarelinksinitscommunicationinfrastructure.TheAustriantunnelingmethodwaseffectiveforlonglargetunnelsneededforbullettrainsandhighway.Timingiscrucialtothemethodssuccess.Aftertheinitialexcavation,theconcretelininghadtobeappliedtotherocksurfaceasquicklyaspossible,leavingnotimeforrocktostartdeteriorating.Thestabilityoftheliningisenhancedbyusingironrodscalledrockbolt.Therockisdrilledtoreceivethem.Boltsarecementeddeepwithintherockandserveasanchors,therodsplateskeeptheconcretesheetsecureandtunnelintact,NATMwasatechnicalrevolution.
Kan-monstraitdividestheislandKuisufromHonsu,Japan’smainisland.Linkingthisislandwasthejobofworldfirstunder-seatunnel,completedin1944.LessonslearnedhereletJapanundertakeadauntingtaskofatunnellinkingHonsuwithnorthislandHokaido.Thetriggerwasthelossoftheferryboatwithover1000lifesin1954.ConstructionoftheSei-Kentunnelbeganin1971.Surmountingmanydifficultiesincludingearthquake,theSei-Kentunnelwasfinishedin1988,HonsuandHokaidowasjointedbythelongesttunnelintheworld.
TechnologydevelopedfortheKan-monandSaikantunnelsplayamajorrollinbuildinganothertunnel,halfaworldaway,theEuro-tunnelunderEnglishchannel.Thisisthebreakthrough,thefinalmoment.Untilthismoment,Britain,theisland,wasodd-man-outinEurope,nowsymbolicallyatleast,thatspecialstatushascometoanend,thanksinparttothisremarkablemachine.
TheEuro-tunnelnowlinkstheBritaintothecontinentofEurope.Over15,000,000peoplecurrentlytaketheferryorhovercrafteachyear.Thechunnel,asitiscalled,wasbornoftheconjunctionofthepoliticalimaginationandmodernengineering.ItiscertaintobecomeamajorlinkintheinfrastructureofanewunitedEurope.June1993sawthefirsttestrunofthetrainfromFrancetoEngland.EventuallyLondonandPariswouldbejust3hoursapart.ThetunnelrunsbelowtheoceanflooroftheEnglishchannelfor38km,thoughitsoveralllengthisnear50km.Itisstrictlyforrailways,andwhenitisinfullservice,willrun10trainseveryhour.Thecartrainswillcarrytrucksofupto40tons.TheconstructionoftheEuro-tunneltookamere3years,thisisinpartduetofavorablegroundconditions,andinparttotechnology.
ThedreamofatunnelunderEnglishchannelhasbeenaroundforatleastacoupleofhundredyears.In1876,queenVictoriyandNapolean3rdagreedtomakeithappen.Drillingwasdoneonthebothsidesofthechannel.Onecanstillseetheremainsofthisshort-livedenterprisenearFolkstone.Techniquesusedthenfordrillingthroughchalkwasprimitiveprecursorsforthoseweusetoday.Themachinesthemselvesweresteampoweredprototypeoftheoneusedin1990toexcavatethechunnel.Politicshaltedthisprojectafterabrief2km,andthedreamlaydormantforanother100years.
Inthemodernworldofthe1980s,9mdiameterJapanesemachinesplayedapartinunifyingEurope.11ofthesetunnelingmachineswereusedtodigtheEuro-tunnel.FranceandBritainmobilizedtheirengineeringpower.Verticalpitsweredugonbothsidesofchannel.Fromthebottomofthepits,tunnelmachinesbegantodighorizontally.Therotatingcutterisaddedatthefrontendofacylinderofsteelwhichencasesandprotectsthewholemachine.Behindthecutter,anapparatusassemblestheconcretetunnelliningwhileexcavationproceeds.Whenaringofconcreteiscomplete,aseriesofhydraulicjackspushesagainstitsrim,andthewholemachineadvances.It’scalledashieldmachine.Itbuildsasitdrills,andtrailsthefinishedlininganditsownsupportservicesbehindit.Thisistheshieldconstructionmethodatitsbest.
Themainproblemencounteredbyengineersbuildingunder-seatunnelsiswaterseepage.Inthecaseofthechunnel,thegeologywasbenign.Astratumofbluechalkrunning40mbelowthechannelfloorresistswaterpenetration.Butthelayerisonly20to30mthick,socarefulsubterraneannavigationisessential.Theshieldmachineisnotsuitedfordrillingincomplexorunstablestrata,butit’sidealforbluechalk.Sometimes,themachinedug50maday,3timesfasterthanexpected.Onanaverageday,20,000tonsofmaterialwerepulverizedandcarriedtothesurface,enoughtofill2000dumptrucks.Theconstructionoftheliningofcoursehadtokeepupthepacewiththeexcavation.The8tonsconcretesegmentofthecylindricalwallwasautomaticallyappliedtothewallofthetunnel.Thetunnelisalmost8macross.Togetherthebluechalklayerandlatestshieldconstructiontechnology,letthetunnelunderEnglishchannelbebuiltinrecordtime.50kmin42months.
TheshieldmethodideawasdevisedinBritainin1818,atthepeakofindustryrevolution.ThefirsttunnelbuiltwiththismethodgoesundertheriverThames.TheinventorwasacreativeengineercalledMarcBrunel.ThatfirsttunnelisstillapartofinfrastructureoftheLondonunderground.WappingstationstillusedasverticalshaftfromthebottomofwhichBrunelmachineboredbelowtheriver.Atthetime,manypeoplethoughtthegroundbelowtheriverwastoounstabletopermitconstructionatunnel,butBrunelwithhisinventionprovedthemwrong.Histunnelhassurvivedformorethan150years.
MarcBrunelownedalumbermill,itwastherethathefoundthecluewhichledhimtoinventashieldmachine.MarcBrunelwasintriguedbythelittleholeswhichareoftenseeninoldlumber.Theholewasmadebyshipworm,theirmolluserelatedtoclams.Atthattime,Londondockswerefullofshipsfromallovertheworld,andtheirhallswerefullofworms.Thesecreaturesjustmillimetersthick,maygrowtobetenscentimeterslong.Theyboreintowoodusingtheirtinyshellstodothedrilling.Astheyprogress,theysecreteasubstancewhichcoatsandtoughenstunnelwallsagainstcompressioncollapse,thewhitesubstancehereistheshipwormtunnellining.ThenotionofboringandbuildingsimultaneouslyinspiredBrunel.Thewallsofthetunnelheconceivedwerenotconcrete,butbrick,andconstructionwasprimitivebymodernstandards,butthisishowitbegan.MarcBrunelwasborninFrancebutcametoliveandworkinEngland.Hishomelandshavenowbeenlinkedbyhisinventioninspiredbyaclam,theshieldconstructionmethod.
ThelargestandmostadvancedshieldmachinesarenowbeingmanufacturedinJapan.Thisoneis14mindiameter,andwillweight3000tons.Meanwhile,atinysensorcontrolsitsautomatedfunctions,itsnervoussystem.Thesesensorswillbeitseyesandfingersforwatchingandfeeling.Theactivitiesofthegiantautomaticwallconstructeraredirectedinaccordancewiththeinformationdeliveredbylasersensors.Theyguidetheassemblytoatolerancelessthan1mm.Sensorswillbestationedatover100pointsonthemachine.Thecuttingbladesteethdeterminethespeedofexcavation.MostofthesoilinJapanisacomplexvarietyofstrata,andcuttershavetocopewiththatvariety.Bladesaremadeofexceptionaldurablematerialsliketungstencarbideandcarbonsteel.ShieldmachinesarenowbeingusedextensivelyinJapanesecitiesforsubwaysandsewagesystems.
Tokyobayistodayashowcaseofmostuptodatedevelopmentsininfrastructuretechnology.A15kmov
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