An effective stress based numerical model for hydro-mechanical analysis inunsaturated porous media

A fully coupled flow-deformation model is presented for the behaviour of un saturated porous media. The governing equations are derived based on the eq uations of equilibrium, effective stress concept, Darcy's law, Henry's law, and the conservation of fluid mass. Macroscopic coupling between the flow and deformation fields is established through the effective stress paramete rs. The microscopic link between the volumetric deformations of the two por e system (i.e. the pore-air and the pore-water) is established using Betti' s reciprocal theorem. Both links are essential for a proper modelling of fl ow and deformation in unsaturated porous media. The discretised form of the governing equations is obtained using the finite element technique. As app lication of the model, experimental results from several laboratory tests r eported in the literature are modelled numerically. Good agreement is obtai ned between the numerical and the experimental results in all cases.