超深桩基础的有效应力地震反应有限元分析

采用有效应力动力分析方法，通过三维有限元数值分析手段，对某长江大桥索塔超深钢围堰加钻孔灌注桩基础进行了地震反应性状分析，对超深桩基础的震陷、地震反应加速度及振动孔隙水压力等动力特性进行了研究。计算结果表明：在地震作用下，桩基发生了较大永久变形，水平位移表现为桩侧土体向桩挤压，桩下部土体向外运动；桩侧附近的地震振动孔隙水压力较小，液化度也较小，相对于天然地基，桩基有较好的抗震性能；桩基础在桩顶部位动力反应相对较大，且边桩的动力反应比中桩的动力反应要大。

Effective stress finite element analysis for seismic response of deep pile foundation

Effective stress dynamic analysis method is used to analyze seismic response of super-deep bored-concrete-piles foundation of a bridge across the Yangtze River. By 3-D finite element numerical analysis, dynamic behaviors such as seism-induced permanent deformation, acceleration and vibration pore water pressure of the deep pile foundation are studied. The results show that the earthquake led to large permanent deformation, small vibration pore pressure of pile foundation; and also show that the tip of piles and the rim piles have more large dynamic response than other part, but the pile foundation have better anti-seismic behaviors than natural foundation.