霍亮, 王贵宾, 李亚伟, 魏翔, 刘桓兑. 北山沙枣园花岗岩体随机结构面的空间分布[J]. 工程科学学报, 2024, 46(3): 385-396. DOI: 10.13374/j.issn2095-9389.2022.12.17.001
引用本文: 霍亮, 王贵宾, 李亚伟, 魏翔, 刘桓兑. 北山沙枣园花岗岩体随机结构面的空间分布[J]. 工程科学学报, 2024, 46(3): 385-396. DOI: 10.13374/j.issn2095-9389.2022.12.17.001
HUO Liang, WANG Guibin, LI Yawei, WEI Xiang, LIU Huandui. Spatial distribution of the stochastic discontinuities of Shazaoyuan granite masses in Beishan[J]. Chinese Journal of Engineering, 2024, 46(3): 385-396. DOI: 10.13374/j.issn2095-9389.2022.12.17.001
Citation: HUO Liang, WANG Guibin, LI Yawei, WEI Xiang, LIU Huandui. Spatial distribution of the stochastic discontinuities of Shazaoyuan granite masses in Beishan[J]. Chinese Journal of Engineering, 2024, 46(3): 385-396. DOI: 10.13374/j.issn2095-9389.2022.12.17.001

北山沙枣园花岗岩体随机结构面的空间分布

Spatial distribution of the stochastic discontinuities of Shazaoyuan granite masses in Beishan

  • 摘要: 北山沙枣园是我国高放废物处置库的备选场址,该区域中广泛分布的随机结构面是控制岩体变形和核素迁移的关键因素. 选取600 m×600 m×600 m沙枣园岩体为研究对象,采用露头节理调查和钻孔裂隙编录的方法,探究岩体随机结构面的空间分布规律. 首先开展随机结构面的产状分析,并运用基于粒子群的K-means算法开展产状聚类,岩体中主要发育倾角大于65°,走向为NNE向、EW向和NW向的随机结构面,其中钻孔裂隙优势组为295.4°∠68.3°、189.5°∠71.2°、235.6°∠69.2°和66.0°∠33.0°,露头节理优势组为320°∠79°、180°∠77°、282°∠80°和231°∠67°,两者呈现相似特征;其次开展露头节理平面分析,采用Voronoi法剖分岩体,计算节理平均迹长值和中点面密度值表征剖分后的岩体节理发育特征,岩体东北部的平均迹长值约为西南部的一半,而中点面密度在岩体中部最大. 据优势组拆分露头的节理参数值,相对于其他优势组,NE向与NNE向优势组的平均迹长更长,中点面密度值更大;最后开展钻孔裂隙的位置分析,据产状聚类分析结果,绘制不同优势组的走向、倾角深度分布图,裂隙呈现深度不均匀的分布特征,平均线密度为0.11 m–1,在–150 m,–160 m区间达到最大值0.60 m–1,在–310 m,–370 m区间密集发育NNE向裂隙. 研究结果可以为沙枣园区域的高放废物处置提供参考依据.

     

    Abstract: Shazaoyuan granite masses are a substitute location for high-level radioactive waste disposal in China. The widely distributed stochastic discontinuities in the granite bodies in this area are crucial factors that control rock deformation and nuclide migration. The spatial distribution of stochastic discontinuities in the Shazaoyuan granite bodies was examined by considering the outcrop joints and borehole fractures within the range of 600 m×600 m×600 m. First, an analysis of the occurrences of stochastic discontinuities was performed, and the K-means algorithm based on particle swarm optimization was employed to cluster the occurrences. Stochastic discontinuities with dips >65 ° and strikes in the north-northeast (NNE), east-west (EW), and northwest (NW) directions were primarily developed in the rock mass. The dominant sets of borehole cracks were four, namely, 295.4°∠68.3°, 189.5°∠71.2°, 235.6°∠69.2°, and 66.0°∠33.0°, while the dominant sets of outcrop joints were four, namely, 320°∠79 °, 180°∠77°, 282°∠80°, and 231°∠67°, with both sets displaying similar characteristics. Second, planar analysis was performed on the outcrop joints. The Voronoi method was utilized to dissect the rock surface based on the outcrop location. The average trace length value and midpoint surface density value of the outcrop joints were employed to characterize the segmented polygonal rock mass. Based on the calculated values of complete outcrop joints, the average trace lengths in the northeast of the rock mass were about half that in the southwest, whereas the midpoint densities were the highest in the middle of the rock mass. Based on the calculated values of split outcrop joints by the dominant sets, the average trace lengths of the northeast (NE) and NNE oriented discontinuities were longer than those of the other dominant groups. The midpoint plane density values were higher. Finally, a depth analysis of the borehole cracks was performed. Based on the cluster analysis results of the occurrences of borehole cracks, the distribution maps of the strikes and dips of the different dominant sets in borehole cracks with depth were drawn. The borehole cracks demonstrated uneven depth distribution characteristics with an average linear density of 0.11 m–1, reaching the maximum value of 0.60 m–1 in the −150 m, −160 m depth, and the NNE cracks were densely developed in the −310 m, −370 m depth. This research results provide a reference for selecting better locations for storing high-level radioactive waste in this area.

     

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