地下室设计深基坑中英文对照外文翻译文献Word格式文档下载.docx

地下室设计深基坑中英文对照外文翻译文献Word格式文档下载.docx

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ABSTRACT：

Allmajortopicsinthedesignofin-situretainingsystemsfordeepexcavationsinurbanareasareoutlined.Typeofwall,waterrelatedproblemsandwaterpressures,lateralearthpressures,typeofsupport,solutiontoearthretainingwalls,typesoffailure,internalandexternalstabilityproblems.

KEYWORDS:

deepexcavation;

retainingwall;

earthpressure;

INTRODUCTION

Numbersofdeepexcavationpitsincitycentersareincreasingeveryyear.Buildings,streetssurroundingexcavationlocationsanddesignofverydeepbasementsmakeexcavationsformidableprojects.Thischapterhasbeenorganizedinsuchawaythatsubjectsrelatedtodeepexcavationprojectsaresummarizedinseveralsectionsintheorderofdesignroutine.Thesearetypesofin-situwalls,waterpressuresandwaterrelatedproblems.Earthpressuresincohesionlessandcohesivesoilsarepresentedintwodifferentcategories.Groundanchors,strutsandnailsassupportingelementsareexplained.Anchorsaregivenmoreemphasiscomparedtoothersduetowidespreaduseobservedintherecentyears.Stabilityofretainingsystemsarediscussedasinternalandexternalstability.Solutionofwallsforshears,moments,displacementsandsupportreactionsunderearthandwaterpressuresareobtainedmakinguseofdifferentmethodsofanalysis.Apilewallsupportedbyanchorsissolvedbythreemethodsandtheresultsarecompared.Typeofwallfailures,observedwallmovementsandinstrumentationofdeepexcavationprojectsaresummarized.

1.TYPESOFEARTHRETAININGWALLS

1.1Introduction

Morethanseveraltypesofin-situwallsareusedtosupportexcavations.Thecriteriafortheselectionoftypeofwallaresizeofexcavation,groundconditions,groundwaterlevel,verticalandhorizontaldisplacementsofadjacentgroundandlimitationsofvariousstructures,availabilityofconstruction,cost,speedofworkandothers.Oneofthemaindecisionsisthewater-tightnessofwall.Thefollowingtypesofin-situwallswillbesummarizedbelow;

1.Bracedwalls,soldierpileandlaggingwalls

2.Sheet-pilingorsheetpilewalls

3.Pilewalls（contiguous,secant）

4.Diaphragmwallsorslurrytrenchwalls

5.Reinforcedconcrete（cast-in-situorprefabricated）retainingwalls

6.Soilnailwalls

7.Cofferdams

8.Jet-groutanddeepmixedwalls

9.Top-downconstruction

10.Partialexcavationorislandmethod

1.1.1BracedWalls

Excavationproceedsstepbystepafterplacementofsoldierpilesorsocalledkingpostsaroundtheexcavationatabout2to3mintervals.ThesemaybesteelH,IorWFsections.Railsectionsandtimberarealsoused.Ateachlevelhorizontalwalingbeamsandsupportingelements（struts,anchors,

nails）areconstructed.Soldierpilesaredrivenorcommonlyplacedinboredholesinurbanareas,andtimberlaggingisplacedbetweensoldierpilesduringtheexcavation.Variousdetailsofplacementoflaggingareavailable,however,precastunits,in-situconcreteorshotcretemayalsobeusedasalternativetotimber.Dependingongroundconditionsnolaggingmaybeprovidedinrelativelyshallowpits.

Historicallybracedwallsarestrutsupported.Theyhadbeenusedextensivelybeforethegroundanchortechnologywasdevelopedin1970s.Soilswithsomecohesionandwithoutwatertableareusuallysuitableforthistypeofconstructionordewateringisaccompaniedifrequiredandallowed.Strutsupportiscommonlypreferredinnarrowexcavationsforpipelayingorsimilarworksbutalsousedindeepandlargeexcavations（SeeFig1.1）.Groundanchorsupportisincreasinglyusedandpreferredduetoaccessforconstructionworksandmachinery.Walingbeamsmaybeusedoranchorsmaybeplaceddirectlyonsoldierpileswithoutanybeams.

1.1.2Sheet-pilingorSheetPileWalls

Sheetpileisathinsteelsection（7-30mmthick）400-500mmwide.ItismanufacturedindifferentlengthsandshapeslikeU,Zandstraightlinesections（Fig.1.2）.Thereareinterlockingwatertightgroovesatthesides,andtheyaredrivenintosoilbyhammeringorvibrating.Theiruseisoftenrestrictedinurbanizedareasduetoenvironmentalproblemslikenoiseandvibrations.Newgenerationhammersgenerateminimumvibrationand

disturbance,andstaticpushingofsectionshavebeenrecentlypossible.Insoftgroundseveralsectionsmaybedrivenusingatemplate.Theendproductisawatertightsteelwallinsoil.Oneside（inner）ofwallisexcavatedstepbystepandsupportisgivenbystrutsoranchor.Walingbeams（walers）arefrequentlyused.Theyareusuallyconstructedinwaterbearingsoils.

Steelsheetpilesarethemostcommonbutsometimesreinforcedconcreteprecastsheetpilesectionsarepreferredinsoftsoilsif