地铁隧道近距穿越施工对桩基承载力的影响研究

256Vol.25No.620066ChineseJournalofRockMechanicsandEngineeringJune20062005110220060206(1968)[e-mail]1211(1.1000832.510640)U45A10006915(2006)06129006STUDYONEFFECTOFMETROTUNNELINGONCARRYINGCAPACITYOFPILEFOUNDATIONYANGXiaojie1DENGFeihuang2NIEWen1LIGuigang1(1.SchoolofMechanicsandCivilEngineeringChinaUniversityofMiningandTechnologyBeijing100083China2.SchoolofCivilEngineeringSouthChinaUniversityofTechnologyGuangzhouGuangdong510640China)AbstractConstructionoftunnelsinurbanarearequiresassessmentoftheeffectoftunnelingonthestabilityandintegrityofexistingpilefoundations.Thispaperdiscussesthebearingcapacityofpile-foundationundertheeffectofconstructionofmetrotunnelsadjacenttopilefoundationsbasedontheengineeringbackgroundoftheconstructionofNo.2LineofGuangzhouMetroinChina.ThefastLagrangiananalysisofcontinuaisusedtosimulatetheresponseofpilesunderthecompleteprocessofmetrotunneling(deactivationofsoilelementandactivationofthelining).TheadjacentrockaroundthetunnelisclassifiedintothreeregionsRegionI(upperadjacentstratumoftunnel)RegionII(45-upper-lateraladjacentstratumoftunnel)andRegionIII(lateraladjacentstratumoftunnel).Ineachregiononetypicalpileischosentocalculateandanalysesindetail.Numericalsimulationsareperformedconcerningrespectivelyside-frictionforceofpiletipresistanceofpileandpileaxialloading.Contrastinganalysesareperformedbothintheresponseoftypicalpilesindifferentregionsandincomputercalculatingvaluewithfieldmeasuringvalue.Resultsofnumericalsimulationsshowthattheeffectonthecarryingcapacityofpileliesmainlyintheeffectofconstructionmetrotunnelsontheside-frictionforceandthetipresistanceofpile.Theeffectiswidelydifferentfromstratumtostratumwherethepiletipislocatedat.Thecomplicatedrulesofside-frictionforceandtipresistanceofpileresultinthecomplicatedrulesofpileaxialloadingthusitinfluencethecarryingcapacityofpile-foundationatlast.Itisnecessarytotakepositivemeasures256.•1291•suchasstratumgroutingstabilizationorfoundationunderpinningetc.todealwiththecarryingcapacityandthesettlementofpile-foundation.Theresultsarevaluableforsimilarengineeringprojects.Keywordstunnellingengineeringmetrotunnelnumericalsimulationpile-foundationcarryingcapacityofpile-foundationside-frictionforceofpiletipresistanceofpile1[19]J.D.MortonK.H.King[6]N.Loganathan[7]L.T.Chen[8]N.Loganathan[9][10]Q=Qs+Qp(1)QQsQp(1)22.1φ1.2m12(1)(32)(52)(6)(7)(8)(9)1Fig.1Longitudinalprofileofengineeringgeology2Fig.2Plotofrelationshipbetweenpileandtunnel122.2•1292•2006100m60m40mkkGikiikhG∑==18.9ρ(2)i=123kLk=123Lkiρ()ih≈λ0.467.010=−=λλk(3)∑===kiiikkhGkF108.967.0ρ(4)Mohr-Coulombϕθϕθϕcossinsin3cossin22cJJpf−−+=(5)θϕθψsinsin3cossin22JJpg−+=(6)cϕψp2JθLode1.2m7.36.6m0.300.35m2.5m15014(3)12344PKPMPKPM(1)(2)(3)1Table1Physico-mechanicalparametersofmodelmaterialsK/MPaG/MPaρ/(kg·m3)c/kPaϕ/()(1)12.502.1119901016(32)12.126.252090036(5)20.839.6219402623(6)34.0917.5819802025(7)88.8929.6321303325(8)350.88152.6723704132(9)1229.001102.002440503719167.0014375.0026005503016667.0012500.002500550303()Fig.3Excavationsubareaoftunnel(a)(b)4Fig.4Modelmeshforcalculationxyzzyoo256.•1293•3I()II(45)III()ABC55Fig.5Representativepilesandstratumzone666Fig.6Sketchmapofstratumsettlementandpileforce3.156IAA()AAA6A1324IIIBIIIBI()IIB()45B6BB1234IIICIIIIIICC()C6CCBAIIIIII•1294•20063.2AA77AFig.7Curveofaxialforceofthebottom-partofpileA7A2.2MN(3.1MNPMPK)0.9MN0.9MN11231.2MN474112133334A41m1/3A88A1234/MN1234/104256.•1295•8AFig.8Curvesofpileaxialforcebycalculationandobservationrespectively5(1)(2)(3)45(4)(References)[1].[][D].2004.(DengFeihuang.Studyonaffectionofpile-foundationcausedbymetrotunnelconstructionanditsunderpinning[M.S.Thesis][D].BeijingChinaUniversityofMiningandTechnology2004.(inChinese))[2].[J].19976(3)274280.(LiYongshengHuangHaiying.PracticalcalculationalmethodsofthemechanicaleffectofTBMpushingonneighbourpiles[J].JournalofTongjiUniversity19976(3)274280.(inChinese))[3].[J].19979(3)146150.(LiYongsheng.Settlementcontrolofneighborbuildingofdeepfootinggroove[J].SpaceofUnderground19979(3)146150.(inChinese))[4]ForthRAThorleyCBB.HongKongislandlinepredictionsandperformance[A].InMairRJTaylorRNed.ProceedingsGeotechnicalAspectofUndergroundConstructioninSoftGround[C].RotterdamA.A.Balkema1996.677682.[5]MairRJTaylorRNBurlandJB.Predictionofgroundmovementsandassessmentofriskbuildingdamageduetoboredtunneling[A].InMairRJTaylorRN.ed.ProceedingsGeotechnicalAspectofUndergroundConstructioninSoftGround[C].RotterdamA.A.Balkema1996.713718.[6]MortonJDKingKH.Effectsoftunnelingonthebearingcapacityandsettlementofpiledfoundations[A].InProceedingsTunneling79[C].LondonIMM1979.5768.[7]LoganathanNPoulosHGStewartDP.Centrifugemodeltestingoftunnelling-inducedgroundandpiledeformations[J].Geotechnique200050(3)283294.[8]ChenLTPoulosHGLoganathanN.Pileresponsescausedbytunneling[J].JournalofGeotechnicalandGeoenvironmentalEngineeringASCE1999125(3)207215.[9]LoganathanNPoulosHJXuKJ.Grounddeformationsandpile-groupresponsesduetotunneling[A].InProceedingsoftheIIINationalConferenceoftheGeo-InstituteofASCE[C].[s.l.]UniversityofIllinoisatUrbanaChamp