A direct time-domain FEM-SBFEM-SBPML method for soil-structure interaction analysis using quadtree mesh

Abstract

In this paper, a novel direct time-domain numerical method, called the FEM-SBFEM-SBPML, is proposed to study the wave propagation problems in soil-structure interaction (SSI) system with complex geometry and geological condition. In the bounded domain, the structure is modeled as beam element based on the finite element method (FEM), and the surrounding truncated soil is discretized using the scaled boundary finite element method (SBFEM) combined with an efficient quadtree mesh generation technique, respectively. In addition, a solid-modified beam coupling model considering the eccentric effect of the tangential traction at the outer surface of the structures is implemented. The unbounded domain is modeled by a recently proposed scaled boundary perfectly matched layer (SBPML) method, which is a novel high-accuracy absorbing layer method satisfying the radiation condition. As a result, the combined FEM-SBFEM-SBPML approach is capable of modeling SSI with complex geometries and soil properties automatically. Some benchmark tests are conducted to illustrate the accuracy and efficiency of the proposed scheme, and a vibration analysis of a soil-tunnel system is further presented to demonstrate the applicability of the proposed method in engineering.