Numerical study on equivalent permeability tensor of fractured rock masses

Determination of permeability dependence of fracture on stresses and temperatures is the basis of safety evaluation in geological disposal of radioactive waste, geothermal exploitation and underground gas/oil exploitation. By means of the developed temperature-permeability-stress test equipment, permeability variation of an artificial rock fracture is studied under different stresses and temperatures. The test results show that the permeability decreases about a half as pressure increases from 9 MPa to 20 MPa, and the closure of fracture cannot recover its initial state as the pressure decreases. When the temperature increases from 19.7℃ to 56.1℃, the fracture permeability decreases about a half. At the end, transport properties of fractured rock masses, in which the fracture network is generated by Mont Carlo method, are studied by using UDEC code based on the fracture test results. The seepage REV and the corresponding equivalent permeability tensor of the fractured rock masses are obtained.