STUDY ON SOLID-FLUID-COUPLED MODEL AND NUMERICAL SIMULATION FOR DEFORMATION POROUS MEDIA

With the assumption that skeleton, grain and water is compressible, a continuity equation of water is established, based on the theory of immiscible two-phase fluid flow in deformation porous media. The two-phase continuity is simplified by the assumption that the air pressure is constant in the domain. A weak formulation of skeleton equilibrium equation is obtained in terms of general Biot’s theory, and the FEM formulation for the coupled problem is derived though above equations. To verify the transient coupled hydromechanical (HM) model, a process of dry media absorbing water is implemented, the results of numerical research (NUR) show that the model can reflect the law of absorbing process. The model is also used to analyze tunnelling under water table, and the result can simulate a rapid local pressure increase, effective stress decrease, permeability and stability changes in the excavation disturbed zone (EDZ) during construction. Numerical results match some general in-situ experiment conclusion obtained by foreign counterpart.