岩体裂隙连通路径及岩体等效渗透张量参数研究?

在高放核废料的处置中,掌握地下水在裂隙岩体中的渗流规律是当下的关键问题。以甘肃北山岌岌槽一测区为工程背景,通过现场数据测得的裂隙统计参数,应用编制的 MATLAB 语言程序生成全局域内的离散裂隙网络模型,将三维裂隙以圆盘模拟并简化为变截面圆管单元渗流网络,为考虑边缘效应以圆管作为单元体切割基准。通过比较随单元体尺寸增大的三个方向上的等效渗透系数变化趋势得到表征单元体 REV,并在该单元体中计算渗透张量以及应用 Dijkstra 算法识别对应边界方向的最优路径。结果表明:该测区的渗透系数最值分别为 3.62e^-6 m/s与 9.19e^-7 m/s,水平向渗透性最小,竖直向附近最大,基本符合工程实际。

Study on Connected Path of Rock Fracture and Equivalent Permeability Tensor Parameters of Rock Mass

In the disposal of high-level nuclear waste,mastering the seepage law of groundwater infractured rock mass is a key issue at present. With the engineering background of a surveying area inGansu Beishan,the discrete fracture network model in the global domain was generated using theMATLAB code based on the statistical parameters of fracture properties measured by field data. Thethree-dimensional disc-shaped fractures are modeled and simplified as channel element network withvariable cross-sections,and each channel element is cut in the research cube for the consideration ofthe edge effect. Then the Representative Element Volume(REV)is characterized by comparing thetrend of the equivalent permeability coefficient in three directions which changes as the size of researchcube is getting larger;the permeability tensor is calculated and the optimum path of the correspondingboundary direction is recognized by use of the improved Dijkstra algorithm in this REV cell. The re?sults show that the maximum and minimum values of the permeability coefficient of the measured areaare 3.62e^-6 m/s and 9.19 e^-7 m/s,respectively,which has the lowest permeability in horizontal planeand the highest one around the vertical direction,and this results are basically in line with the actualproject. All these programming ideas and simulation results can provide a reference for solving relatedengineering problems.