锦屏一级左岸岩体渗透特性的数值模拟研究

基于RFPA~(2D)-Flow软件,并结合现场压水试验,从表征单元体积(REV)及渗透张量入手,对裂隙岩体的渗透特性进行数值模拟研究。以锦屏一级水电站左岸岩体为例,基于岩体裂隙几何特征,运用蒙特卡罗方法生成岩体裂隙网络模型;模拟计算不同尺寸不同方向上的等效渗透系数,依据类常量与类张量特性初步确定裂隙岩体渗透表征单元体积(REV)及渗透张量,再结合现场压水试验结果修正渗透张量。随着模型尺寸的增大,岩体的渗透性逐渐趋于稳定,表征单元体尺寸的大小约为迹长的4倍,表明基于RFPA~(2D)-Flow数值模拟并结合压水试验确定裂隙岩体渗透张量和REV的方法合理有效。

Numerical Simulation of Permeability of Rock Mass on the Left Bank of Jinping -I

Based on the numerical simulation and finite element analysis software RFPA 2D -Flow and single-hole packer tests ,the two-dimensional representative element volume and permeability tensor was analyzed for fractured rock mass . According to the geometric characteristics of the joints ,such as the length ,the density and the yield of the joints .The random fracture networks of Jinping I hydropower station are generated by using Monte Carlo method ,numerical simula-tion of RFPA2D -Flow is adopted to calculate the equivalent permeability coefficient of different size in different directions of fractured rock masses ,in order to obtain the representative elementary volume and permeability tensor .Then they are further modified by the single-hole packer test results .The results show that as the model size increases ,the permeability of rock gradually begins to stabilize ,the size of REV is about 4 times the length of trace .The method is reasonable and effective to determine the permeability tensor and REV of fractured rock masses combining single-hole packer tests and numerical simulation of RFPA2D -Flow .