Abstract A method of determining the cohesion and internal friction angle of a dual-pore-fracture rock mass was improved by considering fracture connection ratio,and this method was introduced into the elasto-plastic thermo-hydro-mechanical(THM) coupling finite element method(FEM) code. Aiming at a model of hypothetical nuclear waste repository in a saturated dual-pore-fracture rock mass with a laboratory scale,the THM coupling FEM analyses were carried out for two assumed cases with orthogonal fracture sets and oblique-cross fracture sets,respectively. The results show that:compared with the axisymmetric distributions of various field quantities in the case with orthogonal fracture sets,the distributions of pore pressures and flow velocities of underground water are axisymmetric,but the distributions of stresses,fracture pressures and relative flow velocities,plastic zones in the rock mass are non-axisymmetric for the case with oblique-cross fracture sets. A large area of plastic zone occurs in the case with orthogonal fracture sets,but almost no plastic zone is produced in the case with oblique-cross fracture sets. The occurrence of fracture sets strongly influences the states of stress,plastic zone and fracture pressure in rock mass.
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