毕业设计外文翻译.docx

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毕业设计外文翻译

DYNAMICBEHAVIOROFPORTALPARTOFTRAFFICTUNNELINHIGH-INTENSITYEARTHQUAKEAREA

交通隧道在高烈度地震区洞口动态行为的探究

外文翻译

专业名称：

土木工程

年级班级：

道桥08-4班

学生姓名：

张银

指导教师：

徐平

河南理工大学土木工程学院

二○一二年六月十一日

DYNAMICBEHAVIOROFPORTALPARTOFTRAFFICTUNNELINHIGH-INTENSITYEARTHQUAKEAREA

SHENYusheng1,2,GAOBo2,WANGZhengzheng2,WANGYingxue2

1PostdoctoralStationofMechanics,SouthwestJiaotongUniversity,Chengdu610031,

China;email:

***************.

2SchoolofCivilEngineering,SouthwestJiaotongUniversity,Chengdu610031,China;

Abstract:

Alarge-scaleshakingtabletestisaccomplishedonthedynamicresponseandfailuremodesofthetunnel.Theresultisthatthelargestdynamicresponseoftunnelstructureappearsattheside-wallandtheshearorfracturingdamageappearsattheinvert,whichisbasicallythesamedamagestatewithtunnelengineeringin5.12WenChuanearthquake.Theinternalforcevalueoftunnelstructureminishandthenumbersofcracksreduceaftertheshockabsorptionlayerissetupinmodeltest,andoptimizethestressstateoftunnel.Thesurfacecracksoftunnelmodelappearfirstlyatbothspandrelsanddevelopdiagonallyatthetunnelentrance.Thecracksarise"X"-shapedistributiononthesurfaceofthemodelsoil.Therearealotofcircumferentialcracksattunnelportalundertheconditionofdynamicloads,andmostoflongitudinalcracksorobliquecrackscanterminatewhenextendingtothecircumferentialcracks.Sothatitisproposedthatthereshouldbedesignedmoreshockabsorptionseamsinthevicinityoftunnelportalinordertobepropitioustodampingtheearthquakeenergy.

Keywords:

dynamicbehavior,shakingtabletest,high-intensityearthquakearea

1Introduction

Itisregrettablethatthepeople'slivesandpropertyhavesufferedgreatlossesduring"5•12"WenchuanearthquakeinSichuanprovince.Atthesametimetheciviltransportengineeringaredamagedtosomeextent,includingthetunnelengineering.Tunneldamagesurveyshowsthatthetunnelportalsectionisthemosteasilytodestroyandisthemostweakparts（Li,2006）.Especiallyatthehigh-intensityearthquakearea,thestabilityanalysisofthetunnelentrance,portalandsideslopewillbefocusedoninthefieldoftheanti-seismictechnologyresearch.Themechanicalcharacteristicoftunnelliningisaconsiderablycomplexprocess,thegradeofsurroundingrockisvariousandthereareavarietyofnon-linearfeatures（Luo,2008）.Itisaeffectivewaytoresearchthetunnelanti-seismiccharacteristicbytheshakingtabletestintheearthquakeengineeringfieldbecausetheestablishmentofnon-linearequationsofmotionandthenumericalsolutionisstillnotperfect（Chen,2006;Gong,2002;Yang,2003;Zhou,2005）.

Itisinevitabletoencounteranyproblemsthatthetunnelprojectscouldbepossibletoadoptedinthevicinityofthefaultorhigh-intensityearthquakeareaduringtheconstructionofthetrafficengineeringinWesternChinaregions（inparticulartheSouth-West）.ThelinefromYa’antoLuguhighwayisacrosstheseismicfaultsseveraltimes（XianshuiRiverfaultzoneandAnningRiverfaultzone）andtheseismicfortificationintensityisfromⅦdegreestoⅨdegrees,inparticularlyⅩdegreesatlocalregions.Thepeakaccelerationofgroundmotionisfrom0.15g~0.4g,whichparametersaretherelativelargeinthecurrentconstructionofthehighway.

Inthispaper,thedynamiccharacteristicsoftunnelstructureisanalyzedatthemountaintunnelportalaccordingtotheactualengineering,thusthelawofstress-strainandfailuremodeofthetunnelandsurroundingrockareresearchedunderthegroundmotionload,whichprovidesanimportantreferenceforthedesignandconstructionofthehighwaytunnelinhigh-intensityearthquakearea.

2Relyingonengineeringconditionsandshakingtabletestdevice

2.1Geologicalconditions

Modeltestwasaccomplishedinaugust2007,basedoncertaintunnelprojectwherethereisthroughtheregionofseismicfortificationintensityⅨdegreesandmaybeactivefaultsinYa-Luhighway.Basedondrillingandsurfacesurvey,thetunnelstratumismostlytriassicsystem~Jurassicsystem,siltymudstone,peliticsiltstone,quartzsandstone,carbargillite,CenozoicoverlyingHoloceneQuaternarycover.

2.2Shakingtabletest

TheshakingtableattheTractionPowerStateKeyLaboratoryisthemainfacilityforexperimentalresearchintoearthquakeengineeringatSouthwestJiaotongUniversity.Themodeltestadoptsthebi-directionalseismicshaketable,whichtablesizeis2.5mby2.5m,theplatformcapableofcarryingamaximumpayloadof30tandthevibrationmodeisforX,Ytwodirectionandfourfreedomdegrees.Thefrequencyrangeis0.1~30Hz,andthepeakaccelerationofXorYdirectionis1.0grespectively.Itisdrivenhorizontallyandverticallybyfour20kNservoactuatorsgivingfullcontrolofmotionoftheplatformin4DOFsimultaneously.

3Designofmodeltestsimilarparameters

Takingintoaccountthemodelbordereffect,thewidthoftheboxmodelshouldbemorethan6timesthetunnelwidth,thusthesimilarparametersaredetermined（geometrysimilarCL=30,Young’smodulusCE=45,densityCρ=1.5）andShen（2008）describedtherestofphysicalsimilarparameters.

3.1Designofsimilarmaterialforsurroundingrockandsecondarylining

Accordingtothesimilarrelationandthephysico-mechanicalparametersofsurroundingrockinsitu,thesimilarmaterialselectedisconsistedofflyash,riversandandoilaftertheorthogonaltestsarerepeateddozensoftimes.Atlastthesesimilarmaterialwillbemixedaccordingtoacertainsimilarratio.

Thesecondaryliningmaterialselectedisconsistedofplaster,quartzsand,barite,waterbyacertainpercentageofpreparation,whichmechanicalparametersareshowninTable.1.

Table.1Mechanicalparametersofconcretesimilarmaterial

parameters

Designvalue

Theoryvalue

Testvalue

Similituderelation

γ（kN/m3）

25

16.7

17.0

reasonable

E（MPa）

29.5

0.66

0.72

reasonable

σc（MPa）

12.5

0.3

0.426

approximately

4Testmeasurementandscheme

4.1Strainmeasurementoftunnelstructure

Straingaugesarefirstlyarrangedforthetunnelsitewheretheinternalforceanddeformationoftunnelismaximal.Thesensorwireshouldbefirmlyfixedatthesurfaceofthemodelstructureandfetchedoutfromthecertainpositionwherethemodeldisplacementislesseratthatdirection.TheschematicdiagramofmeasurementpointsarelaidinFigure.1inordertoverifythedynamicresponselawoftunnelstructure.

Figure.1LayoutschemeofsensorsFigure.2Accelerationstime-historiescurve

4.2Testload---earthquakewave

TheearthquakewavesadoptedistheartificialwavethatissynthesizedbytheSichuanSeismologicalBureauundertheconditionsofthesiteresponsespectrumsynthesisinmodeltest.Theexceedanceprobabilityofearthquakewavesis2%,theoriginalpeakaccelerationis0.67g,theholdtimeisabout20sinthepartofstrongshock,mostoftheearthquakewavesEnergyislessthan15sandiswithin15Hzinthefrequency（inFigure.2）.

4.3Testscheme

InTable.2,thecase2and3aretostudytheeffectoftheshockabsorptionlayer.Thepolyethylenematerialthatisadoptedtotheshockabsorptionlayercircumfusestheoutsidesurfaceofthetunnellining（theinvertisnotlaid）.

Table.2Testconditionsofmountaintunnelmodel

number

case

remark

1

single-tunnelportal

validatingtheanti-seismiccharacteristicofsingle-tunnel

2

bi-tunnelportal

bi-tunnelhavenotshockabsorptionmeasure

3

bi-tunnelportal

single-tunnelhasshockabsorptionmeasure

5Modeltestresultsandanalysis

5.1Strainresponseanalysisoftunnelstructure

Therearemorethan30straingaugesatthekeypositions,thusthestrainresponselawofthetunnelliningisobtainedbythestraingauges.

InFigure.3,whentheacceleration0.4g（equivalenttodegrees）isinputfromshakingtable,themaximumstrainamplitudevalueofthevaultis22μεinthecase2,whilethecase3isfor6.5με,thusthestrainamplitudevalueisobviouslydecreasedaftertheshockabsorptionmeasureistaken.Themaximumstrainamplitudevalueoftheinvertdonotchangebecausetheshockabsorptionlayerisnotsetattherighttunnelinvert.Soitisobviousforthedampingeffectthattheshockabsorptionmeasuresaretakenfortunnelstructureatthetunnelportal.

a）Straincurveofvaultincase2.b）Straincurveofinvertincase2.

c）Straincurveofvaultincase3.d）Straincurveofinvertincase3.

Figure.3Time-historiesofstrainatdifferentpointsofright-tunnel（a=0.4g）

Thestructuralstrainvaluesrecordedfromvariousmeasuringpointsdonottendtobezeroafterthevibrationisover,whichphenomenonismainlyduetotherockandsoilproducingpermanentdeformationaroundthetunnelstructureundertheconditionofthedynamicloading,sothattheadditionalseismicstrainsoccurontunnelstructure

5.2Patternsofdamageofmodeltestcomparativeanalysis

Therearevariouscracksonthesurfaceofthesimilitudematerialinbothcases,butthosecracksoftunnelmodelappearfirstlyonbothspandrelsandthendevelopdiagonally.InFigure.4a,thecracksarise"X"-shapedistributiononthesurfaceofthemodelsoilandthemodelsoilcracksofrighttunnelaremorethanlefttunnelatthesurfaceoftunnel.Thereisa45°anglebetweenthedirectionofcracksandthetunnellongitudinaldirection,thenumbersofcracksinrighttunnelclosetothesideofborderarelessthantheothersideandthereappearalotofrun-throughcracksonthesurfaceofthemodelsoilduetosmalldistanceofbothtunnels.

a）case2（noshockabsorptio