液化侧扩流场地桩基动力反应振动台试验数值模拟

针对已完成的振动台试验,采用OpenSees数值模拟计算平台,建立液化侧扩流场地群桩振动台试验数值模型。该模型中,采用线弹性梁柱单元模拟桩和挡墙,采用刚性连接单元和零长度单元模拟桩-土界面。自由水体通过施加节点孔压和节点力模拟。引入多屈服面塑性本构模拟饱和砂层,采用两相完全耦合的u—p形式模拟土体位移和孔压。通过对比振动台试验结果表明,建立的有限元数值模型能够可靠地再现砂层和桩基的动力响应,进而验证数值模型的可靠性。同时,针对两个代表性时刻,分析了桩-土体系的侧向变形响应。所采用的分析方法和相关结论也为同类桩-土体系数值模拟提供一般性分析方法和思路。

Numerical Simulation of Shake-table Experiment on Dynamic Response of Pile Foundation in Liquefaction-induced Lateral Spreading Ground

A finite element model on dynamic soil-pile interaction was established based on the finished shake-table experiment by mean of OpenSees computational platform in this study. In the numerical modeling, pile and quay wall were represented by the linearly elastic beam-column element. The soil-pile interface was reproduced using rigid link element and zero length element. The water was simulated by applying nodal pore pressure and corresponding nodal force. The saturated sand was modeled by employing the multi-yield surface plastic constitutive model. A two-phase fully coupled up formulation was used to simulate soil displacement and pore pressure. The finite element model can well produce the dynamic response of the sand stratum and pile foundation compared with the results of shake-table experiment, which also further validate the reliability of the finite element model. Meanwhile, the deformation response of soil-pile system was analyzed based on two representative time steps. The analysis technique as well as the derived insights presented in this study provides the general analysis procedure and approach to the numerical modeling of general soil-pile system configuration.