饱和软黏土中沉桩以及随后固结过程的数值模拟

考虑土体的K0沉积过程,利用Flac2D软件对沉桩以及随后的固结过程进行了模拟.模拟过程前,首先对沉桩前不同应力历史土体中的原位有效应力和剪切模量的取值方法进行了分析.通过数值模拟,得到了不同应力历史土体中沉桩后孔隙水压力分布、有效应力场,以及孔压完全消散时的桩侧有效应力场.分析了不同应力历史、不同初始含水量、不同剪切模量对固结完成后桩侧土体不排水抗剪强度提高幅度的影响,探讨了土体结构性对沉桩后桩侧土体的孔隙水压力以及固结完成时桩侧土体径向有效应力、不排水抗剪强度的影响.传统圆孔扩张理论将沉桩过程看作是一个平面应变问题,忽略了问题的三维本质,本文根据应力路径的相似性给出了考虑空间性的办法.

Numerical Simulation of Pile Installation and Subsequent Consolidation in Clay

Flac 2D was used to simulate pile installation and the subsequent consolidation, considering one dimensional consolidation in clay. The parameters selected for Flac code, such as initial effective stress and shear modulus of different stress history before installation, were analyzed. The effective stress and excess pore pressure of different overconsolidation ratio after installation were obtained. After the complete dissipation of excess pore pressure, the effective stress field around pile was generated. The effects of stress history, initial water content, initial shear modulus on undrained shear strength of soil were investigated, and the influence of soil structure on excess pore pressure after installation, and on radial effective stress and undrained shear strength after consolidation was also discussed. The traditional cavity expansion theory takes it as a plane strain assumption, which ignores the three dimensional nature of this problem.