地下室設(shè)計(jì)深基坑中英文對照外文

翻譯文獻(xiàn)中英文對照外文翻譯 （文檔含英文原文和中文翻譯） DeepExcavations ABSTRACT：Allmajortopicsinthedesignofin-situretainingsystemsfordeepexcavationsinurbanareasareoutlined.Typeofwall,waterrelatedproblemsandwaterpressures,lateralearthpressures,typeofsupport,solutiontoearthretainingwalls,typesoffailure,internalandexternalstabilityproblems.KEYWORDS:deepexcavation;retainingwall;earthpressure; INTRODUCTIONNumbersofdeepexcavationpitsincitycentersareincreasingeveryyear.Buildings,streetssurroundingexcavationlocationsanddesignofverydeepbasementsmakeexcavationsformidableprojects.Thischapterhasbeenorganizedinsuchawaythatsubjectsrelatedtodeepexcavationprojectsaresummarizedinseveralsectionsintheorderofdesignroutine.Thesearetypesofin-situwalls,waterpressuresandwaterrelatedproblems.Earthpressuresincohesionlessandcohesivesoilsarepresentedintwodifferentcategories.Groundanchors,strutsandnailsassupportingelementsareexplained.Anchorsaregivenmoreemphasiscomparedtoothersduetowidespreaduseobservedintherecentyears.Stabilityofretainingsystemsarediscussedasinternalandexternalstability.Solutionofwallsforshears,moments,displacementsandsupportreactionsunderearthandwaterpressuresareobtainedmakinguseofdifferentmethodsofanalysis.Apilewallsupportedbyanchorsissolvedbythreemethodsandtheresultsarecompared.Typeofwallfailures,observedwallmovementsandinstrumentationofdeepexcavationprojectsaresummarized.1.TYPESOFEARTHRETAININGWALLS IntroductionMorethanseveraltypesofin-situwallsareusedtosupportexcavations.Thecriteriafortheselectionoftypeofwallaresizeofexcavation,groundconditions,groundwaterlevel,verticalandhorizontaldisplacementsofadjacentgroundandlimitationsofvariousstructures,availabilityofconstruction,cost,speedofworkandothers.Oneofthemaindecisionsisthewater-tightnessofwall.Thefollowingtypesofin-situwallswillbesummarizedbelow;1.Bracedwalls,soldierpileandlaggingwalls2.Sheet-pilingorsheetpilewalls3.Pilewalls(contiguous,secant)4.Diaphragmwallsorslurrytrenchwalls5.Reinforcedconcrete(cast-in-situorprefabricated)retainingwalls6.Soilnailwalls7.Cofferdams8.Jet-groutanddeepmixedwalls9.Top-downconstruction10.PartialexcavationorislandmethodBracedWallsExcavationproceedsstepbystepafterplacementofsoldierpilesorsocalledkingpostsaroundtheexcavationatabout2to3mintervals.ThesemaybesteelH,IorWFsections.Railsectionsandtimberarealsoused.Ateachlevelhorizontalwalingbeamsandsupportingelements(struts,anchors,nails)areconstructed.Soldierpilesaredrivenorcommonlyplacedinboredholesinurbanareas,andtimberlaggingisplacedbetweensoldierpilesduringtheexcavation.Variousdetailsofplacementoflaggingareavailable,however,precastunits,in-situconcreteorshotcretemayalsobeusedasalternativetotimber.Dependingongroundconditionsnolaggingmaybeprovidedinrelativelyshallowpits.Historicallybracedwallsarestrutsupported.Theyhadbeenusedextensivelybeforethegroundanchortechnologywasdevelopedin1970s.Soilswithsomecohesionandwithoutwatertableareusuallysuitableforthistypeofconstructionordewateringisaccompaniedifrequiredandallowed.Strutsupportiscommonlypreferredinnarrowexcavationsforpipelayingorsimilarworksbutalsousedindeepandlargeexcavations(SeeFig).Groundanchorsupportisincreasinglyusedandpreferredduetoaccessforconstructionworksandmachinery.Walingbeamsmaybeusedoranchorsmaybeplaceddirectlyonsoldierpileswithoutanybeams.Sheet-pilingorSheetPileWallsSheetpileisathinsteelsection(7-30mmthick)400-500mmwide.ItismanufacturedindifferentlengthsandshapeslikeU,Zandstraightlinesections(Fig.).Thereareinterlockingwatertightgroovesatthesides,andtheyaredrivenintosoilbyhammeringorvibrating.Theiruseisoftenrestrictedinurbanizedareasduetoenvironmentalproblemslikenoiseandvibrations.Newgenerationhammersgenerateminimumvibrationand disturbance,andstaticpushingofsectionshavebeenrecentlypossible.Insoftgroundseveralsectionsmaybedrivenusingatemplate.Theendproductisawatertightsteelwallinsoil.Oneside(inner)ofwallisexcavatedstepbystepandsupportisgivenbystrutsoranchor.Walingbeams(walers)arefrequentlyused.Theyareusuallyconstructedinwaterbearingsoils.Steelsheetpilesarethemostcommonbutsometimesreinforcedconcreteprecastsheetpilesectionsarepreferredinsoftsoilsifdrivingdifficultiesarenotexpected.Steelpilesmayalsoencounterdrivingdifficultiesinverydense,stiffsoilsorinsoilswithboulders.Jettingmaybeaccompaniedduringtheprocesstoeasepenetration.Steelsheetpilesectionsusedinsuchdifficultdrivingconditionsareselectedaccordingtothedrivingresistanceratherthanthedesignmomentsintheproject.Anotherfrequentlyfacedproblemistheflawsininterlockingduringdrivingwhichresultinleakagesunderwatertable.Sheetpilewallsarecommonlyusedfortemporarypurposesbutpermanentcasesarealsoabundant.Intemporary workssectionsareextractedaftertheirserviceisover,andtheyarereusedaftermaintenance.Thisprocessmaynotbesuitableindenseurbanenvironment.PileWallsIn-situpileretainingwallsareverypopularduetotheiravailabilityandpracticability.Therearedifferenttypesofpilewalls(Fig.).Incontiguous(intermittent)boredpileconstruction,spacingbetweenthepilesisgreaterthanthediameterofpiles.Spacingisdecidedbasedontypeofsoilandlevelofdesignmomentsbutitshouldnotbetoolarge,otherwisepiecesoflumpsetc.dropandextraprecautionsareneeded.Cohesivesoilsorsoilshavingsomecohesionaresuitable.Nowatertableshouldbepresent.Acceptableamountofwateriscollectedatthebaseandpumpedout.Commondiametersare,,m.Walingbeams(usuallycalled?breastingbeams)areTangentpileswithgroutinginbetweenareusedwhensecantpilingordiaphragmwallingequipmentisnotavailable(incaseswheregroundwaterexists).Poorworkmanshipcreatessignificantproblems.Secantboredpilewallsareformedbykeepingspacingofpileslessthandiameter(SThereisalsoneedforplacefortheplant.Itmaybeconstructed“hard-hard”aswellas“soft-hard”.“Soft”concretepilecontainslowcementcontentandsomebentonite.Primaryunreinforcedpilesareconstructedfirstandthenreinforcedsecondarypilesareformedbycuttingtheprimarypiles.Pileconstructionmethodsmayvaryindifferentcountriesforalltypeofpilewallslikefullcasingsupport,bentonitesupport,continuousflightauger(CFA)etc.mostlyreinforcedconcretebutsheetpilesectionsorsteelbeamsarealsoused. DiaphragmWallsDiaphragmwallprovidesstructuralsupportandwatertightness.Itisaclassicaltechniqueformanydeepexcavationprojects,largecivilengineeringworks,undergroundcarparks,metropitsetc.especiallyunderwatertable.Thesereinforcedconcretediaphragm(continuous)wallsarealsocalledslurrytrenchwallsduetothereferencegiventotheconstructiontechniquewhereexcavationofwallismadepossiblebyfillingandkeepingthewallcavityfullwithbentonite-watermixtureduringexcavationtopreventcollapseoftheexcavatedverticalsurfaces.Wallthicknessvariesbetweenmandm.Thewallisconstructedpanelbypanelinfulllengthsare2mto10m.Shortlengths(m)areselectedinunstablesoilsorunderveryhighsurcharges.Nowadaysdepthofpanelswaterstopsexceeded100m,excavationdepthsexceeded50m.DifferentpanelshapesotherthantheconventionalstraightsectionlikeT,L,H,Y,+arepossibletoformandusedforspecialpurposes.Panelexcavationismadebycableorkellysupportedbucketsandbyarecentdesigncalled?cutteror?hydrofraisewhichisapairofhydraulicallyoperatedrotatingdisksprovidedwithhardcuttingtools.Excavationinrockispossible.Slurrywalltechniqueisaspecializedtechniqueandapartfromthebucketortheframecarryingthecutterequipmentlikecrawlercrane,pumps,tanks,desandingequipment,airlifts,screens,cyclones,silos,mixers,extractorareneeded.Tremieconcreteisplacedintheslurrystartingfromthebottomafterloweringreinforcement cages.Jointbetweenthepanelsisasignificantdetailinwaterbearingsoilsandsteelpipe,H-beamorwaterstopsareused.ReinforcedConcreteRetainingWallsExcavationinStagesItisacommontypeofstagedexcavationwallusuallysupportedbygroundanchors.Soilswithsomecohesionaresuitablebecauseeachstageisfirstexcavatedbeforeformworkandconcreteplacement.Nowatertableorappreciableamountofwatershouldbepresent.Sometimesmicropilesupportisgivenifrequiredduetoexpectedcave-ins.SoilNailWallsSimilartothemethodaboveexcavationismadestepbystep(to2mhigh).Shotcreteiscommonforfacingandwiremeshisused.Softfacingisalsopossiblemakinguseofgeotextiles.Holeisdrilled,ordinarysteelbarsarelowered,andgroutisplacedwithoutanypressure.Soilshouldbesomewhatcohesiveandnowatertableorsignificantwaterflowshouldbepresent.CofferdamsCofferdamisatemporaryearthretainingstructuretobeabletomakeexcavationforconstructionactivities.Itisusuallypreferredinthecoastalandseaenvironmentlikebridgepiersandabutmentsinrivers,lakesetc.,wharves,quaywalls,docks,breakwatersandotherstructuresforshoreprotection, largewaterfrontstructuressuchaspumphouses,subjectedtoheavyverticalandhorizontalloads.Sheetpilingiscommonlyusedinvariousformsother thanconventionalwallslikecircularcellularbodiesordoublewallsconnectedinsideandfilledwithsand.Stabilityismaintainedbysheetingdrivendeeperthanbase,sandbodybetweensheetingandinsidetierods.Earthembankmentsandconcretebodiesarealsoused.Contiguous,tangent,secantpilesordiaphragmwallsareconstructedincircularshapes,andnointernalbracingoranchoringisusedtoformacofferdam.Reinforcedconcretewalingbeamssupportbyarching.Shaftsarealsomadewiththismethod.Largeexcavationsorprojectdetailsmayrequireadditionallateralsupport.JetGroutandDeepMixedWallsRetainingwallsaremadebysingletotriplerowofjetgroutcolumnsordeepmixedcolumns.Thereisasoilmixedwall(SMW)techniquespeciallydevelopedforwallconstructionwhereHsectionsareusedforreinforcement.Singlereinforcingbarisplacedinthecentralholeopenedforjetgroutcolumns.Anchors,nailsorstrutsmaybeusedforsupport.TopDownConstruction Retainingstructure(generallydiaphragmwall)isdesignedandconstructedaspermanentloadbearingwallsofbasement.Pilesorbarettesaresimilarlyplacedtocompletethestructuralframe.Topslabiscastatthegroundsurfacelevel,andexcavationismadeundertheslabbysmallersizedexcavatorsandcontinueddownformingbasementslabsateachlevel.Therearespecialconnectiondetails.Topdownmethodispreferredinhighly populatedcitycenterswherehorizontalandvertica