动载下砂土体孔压的累积和消散及其参数分析
|
摘要
基于OpenSees有限元软件平台,采用循环荷载下土体的多屈服面模型,对振动台上土体的孔压的累积和消散进行了数值模拟,并与VELACS动力离心机NO.1模型试验结果进行了对比,得到二者有较好的吻合性.进而对影响孔压的有关参数进行了敏感性分析,结果表明:土体孔压变化对饱和土体密度、流体密度、渗透系数、剪缩参数四个参数较为敏感,对剪胀参数及液化参数不敏感.饱和土壤密度、剪缩参数越大,孔压累积与消散速度越快,峰值孔压越大;流体密度越大,孔压累积与消散速度越慢,峰值孔压越小;渗透系数越大,孔压累积越慢、消散越快,峰值孔压越小.随着测点埋深增大,剪缩参数和渗透系数变化对节点峰值孔压的影响更加明显,而饱和土壤密度和流体密度则表现出相反的特点.
On the basis of OpenSees finite element software platform,the accumulation and dissipation of sand pore pressure are numerically simulated on the vibration platform by using the multi-yield surface model of soil under cyclic load. The simulation results are consistent with the experimental results which are obtained by VELACS dynamic centrifuge NO.1 model test. The sensitivity analysis of the parameters affecting the pore pressure is carried out after that. The results show that the change of pore pressure is sensitive to the saturated soil density,the fluid density,the permeability coefficient and the shear contraction parameter,but insensitive to the shear dilatation parameter and the liquefaction parameter. We find the larger the saturated soil density and shear contraction parameter are,the faster the pore pressure accumulates and dissipates,and the higher the peak pore pressure is.The higher the fluid density is,the slower the pore pressure accumulates and dissipates,and the smaller the peak pore pressure is. The larger the permeability coefficient is,the slower the pore pressure accumulates and dissipates,and the smaller the peak pore pressure is. With the increase of the measured depth,the influence of the shear parameters and the permeability coefficient on the peak pore pressure of the node becomes more obvious,while the saturated soil density and the fluid density show the opposite characteristics.
On the basis of OpenSees finite element software platform,the accumulation and dissipation of sand pore pressure are numerically simulated on the vibration platform by using the multi-yield surface model of soil under cyclic load. The simulation results are consistent with the experimental results which are obtained by VELACS dynamic centrifuge NO.1 model test. The sensitivity analysis of the parameters affecting the pore pressure is carried out after that. The results show that the change of pore pressure is sensitive to the saturated soil density,the fluid density,the permeability coefficient and the shear contraction parameter,but insensitive to the shear dilatation parameter and the liquefaction parameter. We find the larger the saturated soil density and shear contraction parameter are,the faster the pore pressure accumulates and dissipates,and the higher the peak pore pressure is.The higher the fluid density is,the slower the pore pressure accumulates and dissipates,and the smaller the peak pore pressure is. The larger the permeability coefficient is,the slower the pore pressure accumulates and dissipates,and the smaller the peak pore pressure is. With the increase of the measured depth,the influence of the shear parameters and the permeability coefficient on the peak pore pressure of the node becomes more obvious,while the saturated soil density and the fluid density show the opposite characteristics.
引文
[1]齐文浩,薄景山.土层地震反应等效线性化方法综述[J].世界地震工程,2007,23(4):221-226.
[2]刘汉龙.土动力学与土工抗震研究进展综述[J].土木工程学报,2012(4):148-164.
[3] KHOEI A R,AZAMI A R,HAERI S M. Implementation of plasticity based models in dynamic analysis of earth and rockfill dams:a comparison of Pastor-Zienkiewicz and cap models[J]. Computers and Geotechnics,2004,31(5):384-409.
[4]刘光磊,宋二祥,刘华北.可液化地层中地铁隧道地震响应数值模拟及其试验验证[J].岩土工程学报,2007,29(12):1815-1822.
[5]高剑飞. OpenSees:一个专用于土木工程的分析软件[J].四川水利,2007,28(5):32.
[6] SIYAHI B,ARSLAN H. Nonlinear dynamic finite element simulation of Alibey earth dam[J]. Environmental Geology,2008,54(1):77-85.
[7]陈永伟,刘显群,王立忠,等.强震作用下松散海床地基的动力响应[J].岩土力学,2011(7):2225-2230.
[8]陈永伟.强震作用下堤坝海床地基液化分析[D].杭州:浙江大学,2010.
[9] LIANG F Y,CHEN H B,HUANG M S. Accuracy of three-dimensional seismic ground response analysis in time domain using nonlinear numerical simulations[J]. Earthquake Engineering and Engineering Vibration,2017,16(3):487-498.
[10] ZIENKIEWICZ O C,MROZ Z. Generalized plasticity formulation and applications to geomechanics[J]. Mechanics of Engineering Materials,1984,44(2):655-679.
[11] ZIENKIEWICZ O C,SHIOMI T. Dynamic behaviour of saturated porous media;The generalized Biot formulation and its numerical solution[J]. International Journal for Numerical and Analytical Methods in Geomechanics,1984,8(1):71-96.
[12]朱百里.计算土力学[M].上海:上海科学技术出版社,1990.
[13] ZIENKIEWICZ O C,CHANG C T,BETTESS P. Drained,undrained,consolidating and dynamic behaviour assumptions in soils[J].Geotechnique,1980,30(4):385-395.
[14] PREVOST J H. A simple plasticity theory for frictional cohesionless soils[J]. International Journal of Soil Dynamics and Earthquake Engineering,1985,4(1):9-17.
[15] MROZ Z. On the description of anisotropic workhardening[J]. Journal of the Mechanics and Physics of Solids,1967,15(3):163-175.
[16] ELGAMAL A,YANG Z,PARRA E. Modeling of cyclic mobility in saturated cohesionless soils[J]. International Journal Plasticity,2003,19:883-905.
[17] ELGAMAL A,YANG Z,PARRA E. Computational modeling of cyclic mobility and post-liquefaction site response[J]. Soil Dynamics and Earthquake Engineering,2002,22:259-271.
[18]董威信.高心墙堆石坝流固耦合弹塑性地震动力响应分析[D].北京:清华大学,2015.
[19]王睿.可液化地基中单桩基础震动规律和计算方法研究[D].北京:清华大学,2014.
[20] YANG Z,ELGAMAL A,PARRA E. Computational model for cyclic mobility and associated shear deformation[J]. Journal of Geotechnical and Geoenvironmental Engineering,2003,129(12):1119-1127.
[2]刘汉龙.土动力学与土工抗震研究进展综述[J].土木工程学报,2012(4):148-164.
[3] KHOEI A R,AZAMI A R,HAERI S M. Implementation of plasticity based models in dynamic analysis of earth and rockfill dams:a comparison of Pastor-Zienkiewicz and cap models[J]. Computers and Geotechnics,2004,31(5):384-409.
[4]刘光磊,宋二祥,刘华北.可液化地层中地铁隧道地震响应数值模拟及其试验验证[J].岩土工程学报,2007,29(12):1815-1822.
[5]高剑飞. OpenSees:一个专用于土木工程的分析软件[J].四川水利,2007,28(5):32.
[6] SIYAHI B,ARSLAN H. Nonlinear dynamic finite element simulation of Alibey earth dam[J]. Environmental Geology,2008,54(1):77-85.
[7]陈永伟,刘显群,王立忠,等.强震作用下松散海床地基的动力响应[J].岩土力学,2011(7):2225-2230.
[8]陈永伟.强震作用下堤坝海床地基液化分析[D].杭州:浙江大学,2010.
[9] LIANG F Y,CHEN H B,HUANG M S. Accuracy of three-dimensional seismic ground response analysis in time domain using nonlinear numerical simulations[J]. Earthquake Engineering and Engineering Vibration,2017,16(3):487-498.
[10] ZIENKIEWICZ O C,MROZ Z. Generalized plasticity formulation and applications to geomechanics[J]. Mechanics of Engineering Materials,1984,44(2):655-679.
[11] ZIENKIEWICZ O C,SHIOMI T. Dynamic behaviour of saturated porous media;The generalized Biot formulation and its numerical solution[J]. International Journal for Numerical and Analytical Methods in Geomechanics,1984,8(1):71-96.
[12]朱百里.计算土力学[M].上海:上海科学技术出版社,1990.
[13] ZIENKIEWICZ O C,CHANG C T,BETTESS P. Drained,undrained,consolidating and dynamic behaviour assumptions in soils[J].Geotechnique,1980,30(4):385-395.
[14] PREVOST J H. A simple plasticity theory for frictional cohesionless soils[J]. International Journal of Soil Dynamics and Earthquake Engineering,1985,4(1):9-17.
[15] MROZ Z. On the description of anisotropic workhardening[J]. Journal of the Mechanics and Physics of Solids,1967,15(3):163-175.
[16] ELGAMAL A,YANG Z,PARRA E. Modeling of cyclic mobility in saturated cohesionless soils[J]. International Journal Plasticity,2003,19:883-905.
[17] ELGAMAL A,YANG Z,PARRA E. Computational modeling of cyclic mobility and post-liquefaction site response[J]. Soil Dynamics and Earthquake Engineering,2002,22:259-271.
[18]董威信.高心墙堆石坝流固耦合弹塑性地震动力响应分析[D].北京:清华大学,2015.
[19]王睿.可液化地基中单桩基础震动规律和计算方法研究[D].北京:清华大学,2014.
[20] YANG Z,ELGAMAL A,PARRA E. Computational model for cyclic mobility and associated shear deformation[J]. Journal of Geotechnical and Geoenvironmental Engineering,2003,129(12):1119-1127.