The method of fundamental solution for elastic wave scattering and dynamic stress concentration in a fluid-saturated poroelastic layered half-plane

摘要

A meshless method based on the method of fundamental solution (MFS) is developed to solve elastic-wave scattering and dynamic stress concentration in a fluid-saturated poroelastic layered half-plane, by utilizing the line sources of cylindrical P_Ⅰ, P_(Ⅱ), and SV waves in a poroelastic layered half-plane. The numerical accuracy and stability of the MFS is verified by examining the boundary conditions and comparison with other methods. Subsequently, the amplification effects on displacement, surface hoop stress and fluid pore pressure around a cavity in a three-layered poroelastic half-plane are investigated. Numerical results indicate that the scattering characteristics strongly depend on parameters including the incident frequency and angle, soil-layer porosity and boundary drainage condition. The amplification effects of a cavity in the poroelastic layered half-plane appear to be more significant than the corresponding case of a homogenous half-plane. The amplitude of the fluid pore pressure on the surface of the cavity is amplified up to five times that of the free field, which also considerably aggravates the dynamic stress concentration around the cavity.