利用CEL(Coupled Eulerian-Lagrangian)有限元大变形方法模拟了不排水条件下软黏土中沉桩施工对桩周土体的影响.利用有效应力的方法实现了修正剑桥(MCC)模型Vumat子程序中超孔压的计算,通过与室内土工试验(一维压缩试验和三轴试验)结果对比证明了子程序的可靠性.将修正剑桥模型的Vumat子程序嵌入到Abaqus/Explicit的CEL方法中用于软黏土中沉桩效应的模拟分析.对计算得到的桩周土体流动、水平位移、超孔压、水平应力的分析表明,所采用的考虑孔压的CEL数值分析方法可以较好地模拟软黏土非排水条件下沉桩效应问题.
CEL (Coupled gulerian-Lagrangian) method was used to model the pile penetration process in soft clay. Firstly, effective stress method was used in the Vumat subroutine to calculate excess pore pressure. Comparison of the experiment results (by odometer test and triaxial test) with the numerical tests demonstrated the reliability of the Vumat subroutine. The subroutine was implemented in the CEL method of Abaqus/Explicit. Pile jacking process in soft clay under undrained conditions was simulated. The soil movements, horizontal displacement, horizontal stress, excess pore pressure were analyzed. The analysis results show that the CEL method which considers excess pore pressures can simulate well the installation effects caused by pile jacking in soft clay.