Wave propagation in fluid-saturated porous media: An efficient finite element procedure

An efficient finite element procedure to analyze wave propagation phenomena in fluid-saturated porous media is presented. The saturated porous medium is modelled as a two-phase system consisting of a solid and a fluid phase. Time integration of the resulting semi-discrete finite element equations is performed by using an implicit-explicit algorithm. In order to remove the time step size restriction associated with the presence of the stiff fluid in the mixture, the fluid contribution to the equations of motion is always treated implicitly. The procedure allows an optimal selection of the time step size independently of the fluid. Depending upon the particular intended applications (e.g., seismic, blast loading,...) the fluid may be assumed incompressible or compressible. Numerical results which demonstrate the accuracy and versatility of the proposed procedure are presented.