Mixed finite element method for coupled hydro-mechanical-mass transfer process in saturated porous media

A mixed finite element method for miscible contaminant transport (mass transfer) process in saturated porous media is presented. The governing mechanisms in contaminant transport model contain convection, mechanical dispersion, molecular diffusion and adsorption. The displacement, strain and effective stress in solid phase; pressure, pressure gradient and Darcy velocity in liquid phase; contaminant concentration, concentration gradient and its flux are treated as independent variables. The variational (weak) form of the governing equations is given on the basis of the extended Hu-Washizu three-field variational principle with particular consideration of the characteristic-based algorithm in eliminating spurious numerical oscillations in solving mass transfer process. The numerical results illustrate good accuracy and efficiency in comparisons with the existing standard four-point quadrature.