Application of 3D time domain boundary element formulation to wave propagation in poroelastic solids

The dynamic responses of fluid-saturated semi-infinite porous continua to t ransient excitations such as seismic waves or ground vibrations are importa nt in the design of soil-structure systems. Blot's theory of porous media g overns the wave propagation in a porous elastic solid infiltrated with flui d. The significant difference to an elastic solid is the appearance of the so-called slow compressional wave. The most powerful methodology to tackle wave propagation in a semi-infinite homogeneous poroelastic domain is the b oundary element method (BEM). To model the dynamic behavior of a poroelasti c material in the time domain, the time domain fundamental solution is need ed. Such solution however does not exist in closed form. The recently devel oped 'convolution quadrature method', proposed by Lubich, utilizes the exis ting Laplace transformed fundamental solution and makes it possible to work in the time domain. Hence. applying this quadrature formula to the time de pendent boundary integral equation, a time-stepping procedure is obtained b ased only on the Laplace domain fundamental solution acid a linear multiste p method. Finally, two examples show both the accuracy of the proposed time -stepping procedure and the appearance of the slow compressional wave, addi tionally to the other waves known from elastodynamics. (C) 2001 Elsevier Sc ience Ltd. All rights reserved.