裂隙岩体内3维裂隙体的分形描述

Fractal Description of Cracks in Rock Mass

针对裂隙岩体研究过程中的裂隙定量化描述及其与强度参数间的对应关系等问题,通过对完整煤岩进行预加载而获取含裂隙的裂隙岩体试件。基于此,对其试件进行CT扫描探测并重构裂隙岩体模型,以获取表征其分布特征的点云数据,然后利用分形理论,采用立方体覆盖法对岩体内3维裂隙体进行定量化描述,并对CT扫描后的裂隙岩体试件进行单轴抗压试验,进而分析其定量描述指标与强度参数间的关系。结果表明:通过CT扫描获取的3维裂隙体点云数据能够很好地表征其空间分布特征;岩体内3维裂隙体具有自相似性,是一种自然分形,其分形维数能够作为其定量描述指标;在统计意义上,裂隙岩体定量评价指标的分形维数与其单轴抗压强度呈对数关系,且随着裂隙复杂程度的提高,其强度参数呈降低趋势。

In order to get the quantitative description index of cracks and the relation between the index and strength parameter during the study of fractured rock mass,the intact coal was used to obtain the specimens of fractured rock mass through earlier loading,and the point cloud dates which represent the distribution of 3-D cracks could be got after CT scanning on fractured rock mass samples and model rebuilding.Lastly,the uniaxial compressive strength of fractured rock mass after scanning was tested and the relation between the index of quantitative description and strength parameter was analyzed.The results showed that the point cloud which was got after CT scanning could represent the distribution status of 3-D cracks in rock mass well.The 3-D cracks in rock mass,a kind of nature fractal,was self-similar,and it's fractal dimension could be as a index of quantitative description for fracture rock mass.The relation between the quantitative description index(fractal dimension) and the uniaxial compression strength of fractured rock mass was a logarithmic relation in the statistical sense,and the trend of strength parameter decreased with the increase of the complexity of rock mass.