考虑波流影响的深水群桩基础桥墩地震反应分析
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摘要
用基于ABAQUS软件为平台的平行计算技术,对考虑波流影响的地基土-群桩-桥墩体系进行三维非线性地震反应数值模拟,土体和墩台以八节点等参单元离散,桩以梁单元离散,采用土体黏塑性记忆型嵌套面本构模型描述土的动力特性,采用动力塑性损伤模型描述混凝土的动力特性;基于Morison公式,采用Stokes五阶波浪理论描述表面波流,波浪力以分布力的形式施加于桥墩之上,分析了考虑和不考虑波流作用时不同地震动作用下群桩基础桥墩的地震反应特性,结果表明:波流作用对桩体加速度反应的影响很小,但对桩体相对位移和弯矩的影响显著,波流作用使桩体弯矩和顺流向的相对位移增大、逆流向的相对位移减小,其影响幅度随流速的增大而增大,波流作用与输入地震动特性密切相关。考虑波流作用对深水大型桥梁群桩基础桥墩地震反应的影响是有必要的。
Based on the ABAQUS software and the parallel computation technology,a 3-D nonlinear FEM was developed to analyze the seismic response of the foundation soil-pile group-pier system including the effects of water wave and fluid.In the analysis model,the soils were represented by 8 nodes solid elements and the viscous-plastic memorial nested yield surface model was used to describe the dynamic nonlinearity of the soils.The piles were represented by the beam elements and the dynamic plastic-damage model was used to describe the dynamic characteristics of the pile and pier.The Stokes fifth-order wave theory was used to describe the surface water waves.The hydrodynamic pressures acting on the surface of the pile or pier structure were calculated by the Morison's formula.The seismic responses of the foundation soil-pile group-pier system under several measured earthquake ground motions were analyzed by utilizing the presented method and the effects of the water wave and fluid were compared and discussed.It was shown that the water wave and the fluid had a few influences on the acceleration response of the piles but had notable influences on the displacements and internal forces of the piles.The moments and relative displacements in the forward flow direction would be increased under the actions of the water wave or fluid.At the meantime,the relative displacements in the opposite flow direction would be reduced.The effects of the water wave or fluid on the seismic response of the piles would rise with the increase of the water velocity.Therefore,it is necessary to consider the effects of the wave or fluid in the design of the bridge foundations in the deep water.
Based on the ABAQUS software and the parallel computation technology,a 3-D nonlinear FEM was developed to analyze the seismic response of the foundation soil-pile group-pier system including the effects of water wave and fluid.In the analysis model,the soils were represented by 8 nodes solid elements and the viscous-plastic memorial nested yield surface model was used to describe the dynamic nonlinearity of the soils.The piles were represented by the beam elements and the dynamic plastic-damage model was used to describe the dynamic characteristics of the pile and pier.The Stokes fifth-order wave theory was used to describe the surface water waves.The hydrodynamic pressures acting on the surface of the pile or pier structure were calculated by the Morison's formula.The seismic responses of the foundation soil-pile group-pier system under several measured earthquake ground motions were analyzed by utilizing the presented method and the effects of the water wave and fluid were compared and discussed.It was shown that the water wave and the fluid had a few influences on the acceleration response of the piles but had notable influences on the displacements and internal forces of the piles.The moments and relative displacements in the forward flow direction would be increased under the actions of the water wave or fluid.At the meantime,the relative displacements in the opposite flow direction would be reduced.The effects of the water wave or fluid on the seismic response of the piles would rise with the increase of the water velocity.Therefore,it is necessary to consider the effects of the wave or fluid in the design of the bridge foundations in the deep water.
引文
[1]Liaw C Y,Chopra A K.Dynamics of towers surrounded by water[J].Earthq.Eng.and Structural Dynamics.1974,3(1):65-72.
[2]Bang-Fuh,Chen.3D Nonlinear Hydrodynamic analysis of vertical cylinder during earthquakes.I:Rigid motion[J].Engrg.Mech.,ASCE,1997,123(5):458-465.
[3]Yamada Y,Kawano K,Iemura H,et al.Wave and earthquake response of offshore structures with soil-structure interaction[C]∥The Japan So-ciety of Civil Engineers.1988:157-166.
[4]Karadeniz,H.Spectral analysis of offshore structures under combined wave and earthquake loadings[C]∥9thInternational Conf.on Offshoreand Polar Eng.Brest:ISOPE,1999:504-511.
[5]Fukusumi T,Uchida,N,Takahashi,D.Response characteristics of soft settled type of offshore structures subjected to harmonic sea wave andearthquake wave[C]∥13thInternational Conf.on Offshore and Polar Eng.Honolulu:International Society of Offshore and Polar Engineers,2003:1007-1012.
[6]Etemad A K,Gharabaghi AR M,Chenaghlou MR.Nonlinear dynamic behavior of fixed jacket-type offshore platforms subjected to simultaneous-ly acting wave and earthquake loads[C]∥23rdInternational Conf.on Offshore Mech.and Arctic Eng.Vancouver:American Society of Mechan-ical Engineers,2004:893-900.
[7]Abbasi M,Gharabaghi A R M.Study the effect of wave directionality on dynamic nonlinear behavior of jack-up subjected to wave and earthquakeloading[C]∥26thInternational Conf.on Offshore Mech.and Arctic Eng.San Diego:American Society of Mechanical Engineers,2007:377-384.
[8]李富荣,陈国兴,王志华.考虑动水压力影响的单柱式桥墩地震反应分析[J].地震工程与工程振动,2008,28(2):55-59.
[9]何晓宇,李宏男.波浪与地震对小尺度桩柱的共同作用研究[J].地震工程与工程振动,2007,27(5):139-145.
[10]Morison J R,O’Brien MP,Johnson J W,et al..The force exerted to surface wave on piles[J].Petroleum Transaction,AME,1950,189:149-154.
[11]Skjelbreia L,Hendrickson J A.Fifth order gravity wave theory[C]∥Proc.of 87th Coastal Engineering Conf,1961.
[12]白德贵.考虑波流影响的桩基础桥墩地震反应分析[D].南京:南京工业大学,2008.
[13]王涛,李家春,呼和敖德,等.波流相互作用对水动力系数的影响[J].水动力学研究与进展,1995,10(5):551-558.
[14]庄海洋,陈国兴,朱定华.土体动力黏塑性记忆型嵌套面本构模型及其验证[J].岩土工程学报,2006,28(10):1267-1272.
[15]Jeeho Lee,Gregory L Fenves.Plastic-damage model for cyclic loading of concrete structures[J].Journal of Engineering Mechanics,1998(4):892-900.
[16]刘晶波,王振宇,杜修力,等.波动问题中的三维时域粘弹性人工边界[J].工程力学,2005,22(6):46-51.
[2]Bang-Fuh,Chen.3D Nonlinear Hydrodynamic analysis of vertical cylinder during earthquakes.I:Rigid motion[J].Engrg.Mech.,ASCE,1997,123(5):458-465.
[3]Yamada Y,Kawano K,Iemura H,et al.Wave and earthquake response of offshore structures with soil-structure interaction[C]∥The Japan So-ciety of Civil Engineers.1988:157-166.
[4]Karadeniz,H.Spectral analysis of offshore structures under combined wave and earthquake loadings[C]∥9thInternational Conf.on Offshoreand Polar Eng.Brest:ISOPE,1999:504-511.
[5]Fukusumi T,Uchida,N,Takahashi,D.Response characteristics of soft settled type of offshore structures subjected to harmonic sea wave andearthquake wave[C]∥13thInternational Conf.on Offshore and Polar Eng.Honolulu:International Society of Offshore and Polar Engineers,2003:1007-1012.
[6]Etemad A K,Gharabaghi AR M,Chenaghlou MR.Nonlinear dynamic behavior of fixed jacket-type offshore platforms subjected to simultaneous-ly acting wave and earthquake loads[C]∥23rdInternational Conf.on Offshore Mech.and Arctic Eng.Vancouver:American Society of Mechan-ical Engineers,2004:893-900.
[7]Abbasi M,Gharabaghi A R M.Study the effect of wave directionality on dynamic nonlinear behavior of jack-up subjected to wave and earthquakeloading[C]∥26thInternational Conf.on Offshore Mech.and Arctic Eng.San Diego:American Society of Mechanical Engineers,2007:377-384.
[8]李富荣,陈国兴,王志华.考虑动水压力影响的单柱式桥墩地震反应分析[J].地震工程与工程振动,2008,28(2):55-59.
[9]何晓宇,李宏男.波浪与地震对小尺度桩柱的共同作用研究[J].地震工程与工程振动,2007,27(5):139-145.
[10]Morison J R,O’Brien MP,Johnson J W,et al..The force exerted to surface wave on piles[J].Petroleum Transaction,AME,1950,189:149-154.
[11]Skjelbreia L,Hendrickson J A.Fifth order gravity wave theory[C]∥Proc.of 87th Coastal Engineering Conf,1961.
[12]白德贵.考虑波流影响的桩基础桥墩地震反应分析[D].南京:南京工业大学,2008.
[13]王涛,李家春,呼和敖德,等.波流相互作用对水动力系数的影响[J].水动力学研究与进展,1995,10(5):551-558.
[14]庄海洋,陈国兴,朱定华.土体动力黏塑性记忆型嵌套面本构模型及其验证[J].岩土工程学报,2006,28(10):1267-1272.
[15]Jeeho Lee,Gregory L Fenves.Plastic-damage model for cyclic loading of concrete structures[J].Journal of Engineering Mechanics,1998(4):892-900.
[16]刘晶波,王振宇,杜修力,等.波动问题中的三维时域粘弹性人工边界[J].工程力学,2005,22(6):46-51.
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