1D infinite element for dynamic problems in saturated porous media

A fully coupled 1D infinite element for frequency domain analysis of wave propagation problems in unbounded saturated porous media is presented. The element wave propagation function is derived using an analytical solution for Blot's formulation (1962). The effectiveness and the accuracy of the infinite element proposed are demonstrated through a simple wave propagation problem in a semi-infinite soil column subjected to a harmonic surface loading. It is shown that an accurate representation of the problem can be obtained by coupling the conventional finite elements with the proposed infinite element. The accuracy of the solution significantly deteriorates when free or fixed boundary conditions are imposed at the truncated boundary instead of the infinite element. (C) 1997 John Wiley & Sons, Ltd.