Combined the modeling technique of random fractured network with discrete numerical method analyzing the rock permeability including two orthogonal fractures, the results proved the feasibility of the numerical methods. And then, a series of numerical experiments were conducted to analyze the permeability variation of the given fractured rock masses considering different geometric parameters of the rock fractures. These numerical simulations showed that the principal permeability increased with the increase of the fracture length and fracture density, and for the trend of the two group fractures, with increase of the trend angle of the fracture No. I, the maximum principal permeability decreased→increased→decreased, and the minimum principal permeability increased→decreased. The varying characteristics can agree with the general seepage law in the fractured rocks, which can give an important research thought and technique method to research on the variation of the rock permeability under complex geological environment.
The rocks with these random fractures are discontinous, inhomogeneous and anisotropic. And also, multi-field coupling effect will change the rock structural property and hydro-mechanical characteristics. Therefore, external loads resulting in different fractures cutting will directly influence on the hydraulic property of the fractured rocks. However, geological investigations indicate that these random fractures obey some probability distribution, and the geometrical characteristics of the factures such as fracture dip angle, trace length and density determines the seepage way. And different geometrical characteristics forms different seepage network, and the seepage characteristics will also change. Therefore, this characteristics of the fractured rocks plays an important role on the geotechnical projects design and safety assessment.
Some researchers (Rutqvist, Makurat, Olsson, Barton, Chuangbing Zhou, et al.) have paid more attention to this topic, in this paper, random fractured network technique and discrete element method (DEM) were forward to research on the different geometrical characteristics affecting rock permeability (Liu Xianshan). This method can deal with the detailed geometrical characteristics and can correctly simulate the permeability.
