Fluid flow and strain localisation in partially saturated porous media

Abstract

Coupling between fluid fingering and strain localization during the imbibition of a partially saturated soil is investigated in this paper. The fluid mixture saturating the granular skeleton is regarded as a non-uniform fluid characterized via a double well Helmoltz free energy endowed with a gradient regularizing contribution. The porous medium is assumed deformable and the associated elasto-plastic constitutive law is described by the "Sinfonietta Classica" plastic model. Because of the higher differential order of the hydraulic problem a mixed finite element method is employed.