A fully coupled model for water flow and airflow in deformable porous media

A fully coupled model is developed to simulate the slow transient phenomena (consolidation) involving flow of water and air in deforming porous media. The model is of the Biot type and incorporates the capillary pressure relationship. The finite element method is used for the discrete approximation of the partial differential equations governing the problem. The temporal discretization error, iteration error and stability error are evaluated. The model is validated with respect to a documented experiment on semisaturated soil behavior. Other examples involving an air storage problem in an aquifer and a flexible footing resting on a semisaturated soil are also presented.