土坝的地震响应及液化无网格法分析
|
摘要
以Biot固结理论的u-p列式作为饱和砂土的控制方程,应用有效循环弹塑性模型建立土的本构关系,并运用更新的Lagrange大变形算法分析液化后土体的大变形行为。利用移动最小二乘法近似推求形函数,再采用伽辽金法对控制方程离散,获得无网格伽辽金法的基本计算方程以进行无网格法分析。通过算例证明了该方法能避免液化大变形有限元分析时由于网格畸变而引起的计算中断问题。将无网格法应用于某坝的地震响应分析。计算结果表明:坝顶的加速度在液化前较输入加速度有一定的放大,在液化后加速度显著减小,且振动周期变长;坝体下部和坝趾处土体相对于其他区域不容易发生液化。
The governing equations of liquefaction of embankment were established based on u-p formulation of Blot's two-phase mixture theory,and a cyclic elastic constitutive model and improved Lagrange large-deformation method were jointly adopted to take both physical and geometrical nonlinearities into account.The shape functions were established by moving least square method.On this basis,the Galerkin method was used to discretize the governing equations and establish the basis function equations of the element-free Galerkin method.The meshless method can avoid the volumetric locking due to large deformation which usually occurred to numerical computations using finite element method.The proposed method was applied to analyze the seismic response of an embankment with height 4.8m.The comparison with the result of finite element method shows that the acceleration at the top of embankment is amplified but it will be reduces sharply after the occurrence of liquefaction,at the same time the vibration periods will be lengthened.Other than the besides regions,the foundation of the embankment and the soil at the dam toe are not easy to be liquefied.
The governing equations of liquefaction of embankment were established based on u-p formulation of Blot's two-phase mixture theory,and a cyclic elastic constitutive model and improved Lagrange large-deformation method were jointly adopted to take both physical and geometrical nonlinearities into account.The shape functions were established by moving least square method.On this basis,the Galerkin method was used to discretize the governing equations and establish the basis function equations of the element-free Galerkin method.The meshless method can avoid the volumetric locking due to large deformation which usually occurred to numerical computations using finite element method.The proposed method was applied to analyze the seismic response of an embankment with height 4.8m.The comparison with the result of finite element method shows that the acceleration at the top of embankment is amplified but it will be reduces sharply after the occurrence of liquefaction,at the same time the vibration periods will be lengthened.Other than the besides regions,the foundation of the embankment and the soil at the dam toe are not easy to be liquefied.
引文
[1]陈飞雄,李宁,谢定义.黑河土石坝的地震响应和液化分析[J].水利学报,2000,(2),22-26.
[2]宫全美,吴世明.肖山电厂粉煤灰坝在地震作用下的液化及动力稳定分析[J].上海铁道大学学报,1999,20(2),52-58.
[3]Lalita G Oka,Mandar MDewoolkar.Effect of existing dams onliquefaction potential analysis of foundationsoils[J].GSP160Dynamic Response and Soil Properties.1-10.
[4]贺向丽,李同春.重力坝地震波动的时域数值分析[J].河海大学学报,2007,35(1):5-9.
[5]Sato T,Matsumaru T.Liquefaction and groundflowanalysis usingthe element free Galerkin method[C]//Proceedings of KKCNNSymposiumon Civil Engineering,2003.
[6]Tang X,Sato T.Effects of multi-directional input motionto responses of pile in liquefiable soils[C]//Proceedings of the37thNational Conference of Japanese Geotechnical Society.2002.
[7]Lancaster P,Salkauskas K.Surfaces generated by moving least squares methods[J].Math.Comput,1981,37:141-158.
[8]Oka F,Yashima A,Tateishi A Yamashita S.Acyclic elasto-plastic constitutive model for sand considering a plastic-strain dependent of the shear modulus[J].Geotechnique,1999,49(5):661-680.
[9]Uzuoka R,Kubo T,Yashima A,Zhang F.Numerical study on3-dimensional behavior of a damaged pile foundation duringthe1995hyogo-ken nanbu earthquake[C]//Proceedings of4thInternational Conference on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics,2001:6-22.
[10]Yuan Di,Tadanobu Sato.Apractical numerical method for large strain liquefaction analysis of saturated soils[J].Soil Dynamics and Earthquake Engineering,2004,24:251-260.
[11]Fusao Oka.Computational modeling of large deformation and the failure of geomaterials[C]//Proceedings of the16th International Conference on Soil Mechanics and Geotechnical Engineering:47-94.
[12]Yuan Di,Tadanobu Sato.Liquefaction analysis of saturated soils takinginto account variationin porosity and permeability withlarge deformation[J].Computers and Geotechnics,2003,30:623-635.
[13]赵剑明,汪闻韶,张崇文.土石坝振动孔压影响因素的研究[J].水利学报,2000,(5):54-59.
[2]宫全美,吴世明.肖山电厂粉煤灰坝在地震作用下的液化及动力稳定分析[J].上海铁道大学学报,1999,20(2),52-58.
[3]Lalita G Oka,Mandar MDewoolkar.Effect of existing dams onliquefaction potential analysis of foundationsoils[J].GSP160Dynamic Response and Soil Properties.1-10.
[4]贺向丽,李同春.重力坝地震波动的时域数值分析[J].河海大学学报,2007,35(1):5-9.
[5]Sato T,Matsumaru T.Liquefaction and groundflowanalysis usingthe element free Galerkin method[C]//Proceedings of KKCNNSymposiumon Civil Engineering,2003.
[6]Tang X,Sato T.Effects of multi-directional input motionto responses of pile in liquefiable soils[C]//Proceedings of the37thNational Conference of Japanese Geotechnical Society.2002.
[7]Lancaster P,Salkauskas K.Surfaces generated by moving least squares methods[J].Math.Comput,1981,37:141-158.
[8]Oka F,Yashima A,Tateishi A Yamashita S.Acyclic elasto-plastic constitutive model for sand considering a plastic-strain dependent of the shear modulus[J].Geotechnique,1999,49(5):661-680.
[9]Uzuoka R,Kubo T,Yashima A,Zhang F.Numerical study on3-dimensional behavior of a damaged pile foundation duringthe1995hyogo-ken nanbu earthquake[C]//Proceedings of4thInternational Conference on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics,2001:6-22.
[10]Yuan Di,Tadanobu Sato.Apractical numerical method for large strain liquefaction analysis of saturated soils[J].Soil Dynamics and Earthquake Engineering,2004,24:251-260.
[11]Fusao Oka.Computational modeling of large deformation and the failure of geomaterials[C]//Proceedings of the16th International Conference on Soil Mechanics and Geotechnical Engineering:47-94.
[12]Yuan Di,Tadanobu Sato.Liquefaction analysis of saturated soils takinginto account variationin porosity and permeability withlarge deformation[J].Computers and Geotechnics,2003,30:623-635.
[13]赵剑明,汪闻韶,张崇文.土石坝振动孔压影响因素的研究[J].水利学报,2000,(5):54-59.
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心