砂井地基固结的三维有限元模型及应用

一维和二维的数值方法对刻画砂井地基的固结都不够准确和全面，但砂井密集地基的完全三维耦合模拟难度比较大。在对称性原理和Biot固结理论基础上，对三维渗流-二维变形的有限单元方法（PDSS法）进行了改进，给出了砂井地基经济合理的三维剖分方案，使PDSS模型能够直接刻画正三角形布局的砂井。砂井重新布置到节点上而非处理成单元，原模型计算中砂井附近径向流的偏离也得到修正。改进的PDSS模型还与反求参数的方法相结合，用于真空联合堆载预压下砂井路基固结变形的工程模拟。

3D finite element modeling of consolidation for sand drained foundations and its application

Numerical simulations based on 1D or 2D methods are insufficient to integrally describe the consolidation behaviors of sand drained foundations. On the other hand, it is very difficult to simulate the coupled three-dimensional consolidation in the situation that sand drains are dense. However, plane deformation and spatial seepage (PDSS) analysis is sufficient and acceptable. On the basis of symmetry principle and Biot’s consolidation theory, the PDSS modeling proposed is improved. A more reasonable scheme of 3D FEM grid is developed for sand drained ground in which drains are distributed on the pattern of equilateral triangle. Drains are located on nodes instead of elements and the special characteristics of radial drainage are considered. The improved model also is connected to an inverse method and applied to an engineering project to analyze the subsidence of a soft foundation preloaded by combined vacuum and embankment as well as the flux of water discharged by sand drains