建筑物地基动力液化的两相介质动力有限元分析

Simulation of seismic liquefaction of subsoil of building based on the theory of two-phase dynamics

应用饱和多孔介质动力学原理分析了建筑物地基的地震液化问题。将地基视为两相介质体系 ,水是可压缩的。根据土力学模型 ,采用双曲线非线性动力本构 ,考虑了砂土的剪胀性 ,刚度退化 ,滞回特性和土水相对运动等因素 ,建立了动力方程组。基于是否考虑渗流问题 ,建立了两种离散形式 :(1)以土骨架位移和水位移为未知量的矩阵方程 ;(2 )以土骨架位移、水位移和孔隙水压力为未知量的矩阵方程。用显式差分法求解 。

Based on soil mechanics the theory of two phase medium dynamics is applied to analyze the seismic liquefaction of subsoil with dynamic nonlinear constitutive relation,soil dilatancy,rigid degradation,hysteresis and relative motion of water and soil taken into account.In the meantime,an artificial boundary condition is coupled to simulate the wave propagation in pore medium.A set of equation for subsoil layers is established in two forms:1.matrix equations with the displacement of soil skeleton and water displacement as variables;2.matrix equations taking pore water pressure,displacement of soil skeleton and the displacement of water as variable.Computer programs for both kinds of form are established.The analysis of an example is used for demonstration.