裂隙岩体渗透系数以及渗透主方向的确定对研究岩体渗透性大小及各向异性具有重要意义。高放废物地质处置库介质岩体的渗透性能将直接影响其使用安全性。本文运用离散裂隙网络模拟的方法对我国高放废物处置库甘肃北山预选区3#钻孔附近裂隙岩体进行了渗透性质分析。通过对3#钻孔171.5~178.0m段压水试验数据的反演,标定了离散裂隙网络渗流模型中的裂隙渗透参数(导水系数T)。利用标定的离散裂隙网络模型对场区裂隙岩体进行了渗流模拟,确定了该区域裂隙岩体的渗流表征单元体(REV)的尺寸大小以及渗透主值和主渗透方向。运用离散裂隙网络模型计算得出的渗透主值的几何均值与现场压水试验计算结果较接近,证明了计算结果的有效性。
Quantification of hydraulic conductivity and principal hydraulic directions of fractured rock mass is very important for its permeability.The hydraulic property of rock mass around geological repository of high-level radioactive waste directly determines its safety in operation.The permeability property of rock mass around the 3# borehole in Beishan Area,Gansu Province is analyzed using the discrete fracture network model.The fracture transmissivity of the fluid flow model is calibrated via simulating the packer test process conducted in the depth range 171.5~178m of the 3# borehole.The REV(Representative Element Volume)size and principal hydraulic conductivity of the rock mass near the 3# borehole are determined via performing the flow calculations based on the tranmissivity calibrated discrete fracture network model.It is found that the results are compared quite well with those obtained through the radial flow continuum porous media model.