Enhanced finite element formulation for geometrically linear fluid-saturated porous media

This contribution is concerned with a new mixed finite element formulation for geometrically linear Terzaghi-Biot type fluid-saturated porous media. To this end, an extended Hu-Washizu type mixed variational principle is presented for fluid-saturated porous continua. Then, a suitable discretization and its implementation are discussed, resulting in an improved element behaviour especially in numerical localization analyses. The intriguing element performance is firstly demonstrated for the case of localization within an elastoplastic compression problem. Finally, an elastoplastic slope stability problem is examined, whereby the new element formulation proves to render more pronounced failure modes as compared with a standard element expansion