连续-离散介质动力耦合模型在斜坡堆积体地震响应分析中的应用  

Application of Continuum and Discrete Medium Dynamic Coupling Model in Seismic Response Analysis of a Deposit Covered Slope

作　　者：张华[1] 陆阳[1] 余建华[2] 

机构地区：[1]西南交通大学土木工程学院,四川成都610031 [2]四川省交通厅公路规划勘测设计研究院,四川成都610041

出　　处：《公路交通科技》2011年第5期6-11,27,共7页Journal of Highway and Transportation Research and Development

基　　金：国家重点基础研究发展计划(九七三计划)资助项目(2008CB425802)

摘　　要：采用有限差分与离散单元外部动力耦合计算方法,研究地震作用下斜坡堆积体变形规律与动力特性,并对堆积体颗粒平行连接强度进行敏感性分析。采用平面应变有限差分网格和平行连接圆盘离散元法分别模拟下伏基岩与上覆堆积体,界面的平滑过渡通过耦合两域取相同时步交替迭代的方法加以实现。动力分析以自重作用下的静力平衡为初始条件,基岩两侧由引入的自由场边界来消除辐射阻尼影响,进而从模型底部输入水平加速度以模拟地震激励。应用上述方法于某斜坡堆积体地震响应分析,结果表明:颗粒平行连接强度为0.5 MPa时,峰值强度为0.05g的Lom a Prieta水平地震加速度激励下材料损伤较小,坡体于地震末仍处于稳定状态;平行连接强度的折减对地震作用下堆积体的损伤程度与变形规律均有重要影响。With a dynamic coupling model that combining finite difference method and discrete element method（DEM）,deformation regularity and dynamic characteristic of deposit covered slope subjected to earthquake loads were analyzed,and sensitivity analysis for parallel bond strength of the deposit particle materials was further presented.In the proposed model,the bedrock and deposit were simulated respectively with plane-strain finite difference meshes and a collection of parallel bonded rigid disks of DEM,and smooth transition across the continuous and discontinuous domains was obtained by imposing the compatibility condition and equilibrium condition along the interfaces,and the same time step was chosen for the two coulping domains in the iteration procedure.After the static equilibrium under gravity loads being obtained,free-field boundaries were adopted for lateral grids of bedrock meshes to eliminate the radiation damping effect in dynamic calculation,and dynamic calculation was performed under excitation of horizontal seismic accelerations inputted from the continuum model bottom.Through above-mentioned calculation procedures,dynamic analyses of a deposit covered slope were conducted.The results show that（1） as the parallel bond strength of the disks is 0.5 MPa,damage extent of the deposit after horizontal excitation of the Loma Prieta wave with peak acceleration of 0.05g are quite small,and the slope body correspondingly keeps stable;（2） reduction for parallel bond strength of disks has significant effects on both the damage extent and deformation rule of the deposits under earthquake loads.

关 键 词：道路工程 斜坡堆积体 动力耦合 地震响应 离散元法 

分 类 号：U416[交通运输工程—道路与铁道工程]