结构面特征及应力边界对岩体渗透系数的影响研究

裂隙岩体介质渗透特性是研究地下水问题的重要参数，不仅取决于结构面产状规律同时与所处地应力环境相关。本文针对裂隙岩体渗透性问题，考虑结构面分布随机性，利用UDEC软件，通过多个数值分析模型，研究了结构面特征和应力边界条件对裂隙岩体等效渗透性的影响。结果表明：裂隙倾角、间距、隙宽和迹长对岩体的渗透特性均有明显影响，裂隙倾角与渗流主方向较为接近时，该方向的岩体渗透系数较高；岩体的渗透系数随裂隙间距的增加呈幂函数降低趋势，随隙宽的增加而增大；各渗透分量均随迹长的增加而增大，但增长速度由快变慢；岩体所赋存环境地应力场对岩体的渗透系数有明显影响，地应力水平的提高会导致有效水力隙宽减小，进而降低岩体的渗透性，渗透系数随地应力的变化基本呈线性关系。

Research on influence of structural plane characteristics and stress boundary on permeability coefficient of rock mass

The permeability of fractured rock mass is an important parameter to study groundwater problems, which not only depends on the occurrence law of structural plane, but also is related to the in-situ stress environment. In this paper, considering the randomness of discontinuity distribution, the influence of discontinuity characteristics and stress boundary conditions on the equivalent permeability of fractured rock mass is studied by using UDEC software and several numerical analysis models. The results show that the dip angle, spacing, width and trace length of fractures have obvious effects on the permeability of rock mass. When the dip angle of fractures is close to the main seepage direction, the permeability coefficient of rock mass in this direction is higher. The permeability coefficient of rock mass decreases as a power function with the increase in crack spacing,and increases with the increase in crack width. Each permeability component increases with the increase in trace length,but the growth rate becomes slower. The in-situ stress field of rock mass has obvious influence on the permeability coefficient of rock mass. The increase of in-situ stress level will lead to the decrease of effective hydraulic gap width, and then reduce the permeability of rock mass. The permeability coefficient changes linearly with the change of in-situ stress.