基于统计均质区方法的裂隙几何及渗流特性评价  

Assessment of fractures geometries and seepage characteristics based on statistical homogeneous zone method

作　　者：李露露 李牧阳 周志超[2] 张秋兰[1] 崔亚莉[1] 邵景力[1] Li Lulu;Li Muyang;Zhou Zhichao;Zhang Qiulan;Cui Yali;Shao Jingli(School of Water Resources and Environment,China University of Geosciences(Beijing),Beijing 100083,China;Beijing Research Institute of Uranium Geology,Beijing 100029,China)

机构地区：[1]中国地质大学(北京)水资源与环境学院,北京100083 [2]核工业北京地质研究院,北京100029

出　　处：《地质科技通报》2023年第4期288-298,共11页Bulletin of Geological Science and Technology

基　　金：核设施退役及放射性废物治理专项项目(科工二司〔2017〕1405号)。

摘　　要：综合分析岩体裂隙几何特征及渗流特性是高放废物处置库场址适宜性评价中关键内容之一。利用北山预选区新场地段中部BS32、BS36和BS39钻孔试验及其周围的裂隙现场调查结果,以裂隙产状及线密度为指标对钻孔进行定量均质区划分,并辅以渗透张量理论得到钻孔裂隙岩体渗透性大小及渗透主方向。研究结果表明:新场地段URL(地下实验室)场址区发育4组优势裂隙,其产状分别为279°∠79°,98°∠76°,227°∠79°和36°∠76°,尤以EW向和NNE向最发育。节理裂隙以陡倾角(>60°)的剪节理为主,同时伴有少量张节理,裂隙倾向、倾角呈正态分布特征。与现场水力试验结果相比较,钻孔整体综合渗透系数处于10^(-13)~10^(-9) m/s数量级范围,主渗透方向主要是NNE向、近EW向及SE向,NNE向及近EW向为裂隙岩体优势渗流通道,其渗透张量主值较大。位于新场地段2条近EW向的F 6,F 7断裂以及与其配套的NNE-EW向次级断裂对新场地段裂隙发育起到宏观控制作用。裂隙岩体渗透性大小主要受裂隙间距和隙宽影响。研究结果可为北山预选区新场地段处置库建设及处置库中核素迁移等工程数值模拟提供必要的数据支撑。[Objective]Comprehensive analysis of fracture geometries and seepage characteristics is one of the prominent components in site suitability assessment of high-level radioactive waste(HLW)disposal repositories.[Methods]To provide a sufficient basis for the construction of the Xinchang underground research laboratory(URL)site in the Beishan preselected area of the HLW disposal repository in China,this paper analyzed the development and distribution of fractures and the seepage characteristics in fractured granite.Based on the borehole tests of BS32,BS36 and BS39 carried out in the middle of the Xinchang site and the field investigation of the surrounding fractures,the orientations and linear density of fractures were used to quantitatively classify the homogeneous zones of the BS32,BS36 and BS39 boreholes.Supplemented by the theory of the hydraulic conductivity tensor,the hydraulic conductivities of fractured rock and the principal directions of fluid seepage in fractured rock with different burial depths were obtained.[Results]The results show that four groups of dominant fractures are developed around BS32,BS36 and BS39 at the Xinchang URL site,with orientations of 279°∠79°,98°∠76°,227°∠79°and 36°∠76°,which are especially dominant in the EW and NNE directions.The fractures are mainly shear-stress formed with steep dips(>60°),accompanied by a few tensile fractures,and the fractures are normally distributed.Compared with the field hydraulic test results,the overall comprehensive hydraulic conductivities of the boreholes are in the range of 10^(-13)-10^(-9) m/s.The main seepage directions are NNE,nearly EW and SE,where NNE and nearly EW are the dominant seepage channels of the fractured rock mass,with larger main permeability tensor values.Two nearly E-W-trending F 6 and F 7 faults and their corresponding NNE-E-trending secondary faults play a macrocontrolling role in fracture development at the Xinchang site.The permeability of fractured rock is mainly affected by the fracture spacing and aperture,

关 键 词：高放废物 地质处置 节理裂隙评价 均质区 渗透张量 

分 类 号：TL942[核科学技术—辐射防护及环境保护]