英语文献报告PPT推荐.pptx

英语文献报告PPT推荐.pptx

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专业英语作业汇报专业英语作业汇报Evaluationofundrainedfailureenvelopesofcaissonfoundationsundercombinedloading作者作者MouraMehravara,OuahidHarirecheb,AsaadFaramarzica.WolfsonSchoolofMechanicalandManufacturingEngineering,LoughboroughUniversity杂志杂志AppliedOceanResearch年月年月2016页码页码129-137GeneralbackgroundAsuctioncaissonconsistsofathin-walledupturnedbucketofcylindricalshapemadefromsteel.Thistypeoffoundationhasproventobeefficientandversatileasasupportforoffshorestructuresandappearstobeaveryattractiveoptionforfutureuseinoffshorewindturbines.Thethincaissonwallfacilitatesinstallationwhenapressuredifferentialisinducedbysuctiononthecaissonlid,whichpushesthecaissontopenetrateintotheseabed.Thisisachievedbypumpingoutthewatertrappedinthecaissoncavityafterinitialpenetrationunderself-weight.Theskirtcanimprovethefoundationbearingcapacitybytrappingthesoilbetweenthemduringundrainedloading.LiteraturereviewandGapAnumberofstudieshavebeenconductedontheinvestigationofbearingcapacitiesofcaissonfoundations.However,inthemostoftheformerstudiesthefoundationwaseitheranalysedasaskirtedstripfoundationusingfiniteelementanalyses（FEA）andupperboundsolutionsorasasurfacecircularfoundationusingthree-dimensionalFEAwithoutconsideringtheskirtlengthinthesimulation.Ontheotherhand,offshorefoundationsarethree-dimensionalandembedded.Theskirtlengthhasaconsiderableimpactontheirbearingcapacities.Onlyfewstudieswereperformedbyconsideringthecaissonfoundationusingthree-dimensionalmodel.Mostoftheseanalysesdidnotcomprehensivelycoveredawiderangeofpracticalembedmentratiosorinvestigateallvertical,horizontalandmomentbearingcapacities.AsummaryofpreviousstudiesonundrainedbearingcapacitiesandfailureenvelopesofshallowfoundationsarepresentedinTable1.gapObjectiveInthepresentstudythemainobjectiveistoperformthree-dimensional（3D）undrainednumericalsimulationstopredictthebearingcapacityofcaissonfoundationsunderuniaxialandcombinedloadingconditions.ThepresentstudyrefersmainlytotheworkdonebyGourvernec,BransbyandRandolph,whichareessentiallyplanestrainanalyses.Ithasbeenjustifiedthatwithinsuchcontext,theassumptionoffullbondingbetweenthecaissonandsurroundingsoilisplausible（especiallythatsuctiondevelopmentattheinterfaceinundrainedconditionpreventsseparation）.Hence,theworkperformedinthecurrentpaperhasbeenlimitedtoasimilarcontext,takingadvantageofefficientnumericalcomputationsandreasonablecomputationaltime.Anextensionofthepresentworkbyimplementinginterfaceswouldshedmorelightontheaccuracyofbothplanestrainand3Dmodels,butsuchanextensionisbeyondthescopeofthepresentpaper.objectiveObjectiveInthispaper,aseriesofthree-dimensionalfiniteelementanalysesusingABAQUSareperformedtoinvestigatetheeffectoftheembedmentdepthonthebearingcapacityofshallowfoundationsinhomogenousundrainedsoil.Differentaspectratiosofcaissonfoundation“L/D=0,0.25,0.5,0.75,1”,whereListheembedmentlengthandDisthecaissondiameterareconsidered.Uniaxialvertical（V）,horizontal（H）andmoment（M）bearingcapacitiesareinvestigatedandpresentedasaseriesofequationstoestimatetheuniaxialultimatevertical,momentandmaximumhorizontalbearingcapacityfactorsofcaissonfoundations.Finally,thecapacitiesofcaissonfoundationsundercombinedVH,VMloadspacearestudiedandexpressedbyfailureenvelopes.IntroductionAsuctioncaissonconsistsofathin-walledupturnedbucketofcylindricalshapemadefromsteel.Thistypeoffoundationhasproventobeefficientandversatileasasupportforoffshorestructuresandappearstobeaveryattractiveoptionforfutureuseinoffshorewindturbines.Thethincaissonwallfacilitatesinstallationwhenapressuredifferentialisinducedbysuctiononthecaissonlid,whichpushesthecaissontopenetrateintotheseabed.Thisisachievedbypumpingoutthewatertrappedinthecaissoncavityafterinitialpenetrationunderself-weight.Theskirtcanimprovethefoundationbearingcapacitybytrappingthesoilbetweenthemduringundrainedloading.Anumberofstudieshavebeenconductedontheinvestigationofbearingcapacitiesofcaissonfoundations.However,inthemostoftheformerstudiesthefoundationwaseitheranalysedasaskirtedstripfoundationusingfiniteelementanalyses（FEA）andupperboundsolutionsorasasurfacecircularfoundationusingthree-dimensionalFEAwithoutconsideringtheskirtlengthinthesimulation.Ontheotherhand,offshorefoundationsarethree-dimensionalandembedded.Theskirtlengthhasaconsiderableimpactontheirbearingcapacities.Onlyfewstudieswereperformedbyconsideringthecaissonfoundationusingthree-dimensionalmodel.Mostofthesean