裂隙岩体三维渗透张量及表征单元体积的确定

 将基于复合单元法的数值试验和现场单孔压水试验相结合，对裂隙岩体的三维渗透张量及表征单元体积(REV)进行研究。首先根据研究域岩体的裂隙统计参数及分布规律，运用蒙特卡罗方法在统计域内生成三维随机裂隙网络，然后利用复合单元法计算不同尺寸岩体试件在不同方向上的等效渗透系数，以此计算岩体的三维渗透张量及REV尺度，最后利用现场单孔压水试验结果来修正裂隙岩体的3个渗透主值。在小湾水电站工程中，运用该方法对坝区岩体的三维渗透特性进行分析，得到修正后的岩体三维渗透张量，分析结果表明，结合单孔压水试验和基于复合单元法的数值试验来确定裂隙岩体的三维渗透张量和REV是合理且有效的。

ESTIMATION OF REPRESENTATIVE ELEMENTARY VOLUME AND THREE-DIMENSIONAL PERMEABILITY TENSOR FOR FRACTURED ROCK MASSES

Both numerical methods and single-hole packer tests are used in study of the representative elementary volume(REV) and three-dimensional(3D) permeability tensor for fractured rock masses. Based on the probability distribution functions and corresponding statistical parameters investigated in field，3D stochastic discrete fracture networks are randomly generated using the Monte Carlo method. The composite element method(CEM) is used to obtain the permeability tensor and REV of rock masses，with a large quantity of calculations concerning different sample sizes in various directions. The permeability tensor is then modified and improved by using single-hole packer test results. Finally, the proposed method is used in determining the permeability properties of dam foundation of Xiaowan hydropower station. The results show that the proposed method is feasible and reliable.