A multi-domain singular boundary method for dynamic analysis of multilayered saturated porous media

The singular boundary method (SBM) is a boundary-only meshless collocation method, but it is not applicable to solve multi-material cases directly with closed-form fundamental solutions. In this study, a semi-analytical boundary-only approach, multi-domain SBM (MD-SBM), is firstly formulated to study the dynamic analysis of multilayered saturated porous media. Firstly, the domain is divided into several subdomains with the consistent material. Then, the singular boundary method (SBM) simulates the dynamic response in each subdomain via a linear combination of fundamental solutions. The source singularity issue is removed by the origin intensity factors (OIFs) rather than singular integrals in the BEM. Finally, the SBM solutions in each layer are coupled by the continuity and compatibility conditions on the interface boundaries between adjacent layers. The SBM does not require domain discretization and desingularizes the source singularity with simple formulas. Thus, it is easy to implement. The MD-SBM is tested to both finite and semi-infinite cases to illustrate its accuracy and feasibility. It is worthnoting that the closed-form fundamental solutions can be directly applied to the semi-infinite cases without requiring additional modifications.