MESH-FREE METHOD FOR PREDICTING THE BEHAVIOR OF SATURATED SOIL

摘要

A numerical strategy of mesh-free method for saturated soil is presented instead of the usual finite element method and its scheme is validated through the simulation of laboratory experiments and practical problems. Among several mesh-free methods, the Element-Free Galerkin Method (EFG) has been enhanced as a general tool for solving partial differential equations in the field of mechanical engineering and the technique is also incorporated into the solution strategy of geomechanical problems. A formulation of the EFG for saturated soil is furnished within the framework of finite deformation to solve a set of governing equations, e.g., the equilibrium for nominal stress rate and the continuity of pore water. Numerical discretization of the weak form of the governing equations leads to an updated Lagrangian scheme. Stable solutions are obtained under consistent shape functions for both soil skeleton and pore pressure which are defined at nodes and integration points by the Moving-Least Square (MLS) interpolation. After examining an accuracy of the computation through drained and undrained tests for soil specimen in comparison with closed ones, numerical results are described to trace the bifurcation phenomena in the relation of load and deflection where several patterns of initial imperfection are given along the surface of soil specimen. Shear banding within a soil specimen can be introduced while avoiding the numerical difficulties which depend on mesh size and type. Feasibility of the computation is also demonstrated in the analyses for the foundation under the embankment loading.