Fundamental Study on the Applicability of Element Free Galerkin Method in the Saturated and Unsaturated Seepage Flow Analysis

A new seepage analysis system using the mismatched mesh is presented. With the rapid performance improvement of the computers in recent years, a large-scale numerical analysis becomes possible. On the other hand, for mesh generation of numerical model, much manual work is still indispensable. The most laborious task in 3D analyses is solid modeling as geometry definition. A detailed model is necessary to understand the flow of the groundwater accurately by simulation. As for the model for groundwater flow analysis, the domains with different characteristics such as the fault zone and aquifer layer must be considered. In addition, depending on the result of the geological survey, we must revise a model many times. We have developed a new system to reduce the cost of such a model making. This system is based on the Element-Free Galerkin Method which is a kind of meshless method. The biggest characteristic of this system is to be able to use the mismatched mesh. Therefore, we make independent meshes for the domains of different characteristics and can put them at any position in the global domain. This system can be applied for the study on the layout of the underground structure. By basic numerical analysis, we inspected the accuracy of this system. The accuracy of the proposed system is similar to the Finite Element Method solution became clear. We investigated the influence of the mesh size on the precision in this system. The numerical examples showed that the solution accuracy of our system is sensitive to the size of the domain of influence that was a parameter peculiar to Element-Free Galerkin Method. However, it can be considered that the sensitivity is not significant for practical use.