Geotechnical problems behavior depends on their interaction with existed fluid phases in their voids. In this research three phase porous media is introduced and it’s governing equations is presented. For solving this set of fully coupled dynamic equations finite element method is applied using elements with displacement and pressure degrees of freedom. Essential drawback of FEM method is in discontinuities modeling. In solid mechanic problems, discontinuity may occur in displacement field, such as crack or contact problems, or in their derivatives, such as multi-material problems. Major soil structures include some internal regions that there are some meshing problems during their FEM...