Based on mixture theory and the double porosity hydromechanical coupling concept

a set of coupled governing differential equations of porous fissured media is derived. The finite element technique has been employed as the numerical methods for solving these equations by using Galerkin finite element methods. Relations relating to rock classification rating RQD and RMR are developed to define changes in effective porosity and hydraulic conductivity that result from the redistribution of strains in disturbed rock mass. A 2-D finite element program and software for solving the double porosity media coupling model is developed. Results obtained from a hypothetical example indicate that the program is reasonable and practical. The program is also used to simulate tunnel excavation; the influence of seepage effect on tunnel ground deformation and seepage field is discussed. The results of numerical calculation show that tunnel liner design is unsafe without considering hydromechanical coupling effect.