基于裂隙产状和迹长划分岩体统计均质区研究

Identification of homogeneous structural domains of jointed rock masses based on joint occurrence and trace length

岩体统计均质区的划分是岩体工程设计的首要步骤,因为不同的均质区内岩体的结构特性和力学特性都存在差异。大多研究考虑产状或者其他单一参数划分岩体统计均质区,却很少有人考虑多参数进行划分研究。考虑了裂隙产状、迹长两个参数,提出了一种划分裂隙岩体统计均质区的新方法,即基于秩和检验评价两个样本之间的相似性,从而实现对裂隙岩体统计均质区的划分。结合工程实例即云南省马吉水电站左岸坝肩某两高程4个平硐的岩体结构统计均质区划分,分析了多参数对裂隙岩体统计均质区划分的影响。研究结果表明:PD241和PD253、PD201和PD241分别划分为一个统计均质区,而PD201和PD251以及PD251和PD253不具有统计相似性。考虑了产状和迹长因素对岩体统计均质区的影响,划分结果较Miller方法更加合理可靠。结合现场调查分析,新方法的结果更加吻合实际情况。

The demarcation of homogeneous structural domains within rock mass is normally the first step of rock engineering design, since mechanical and structural properties vary largely from one homogeneous domain to another. Most of researches focus on occurrence or the other joint parameters to statistically identify homogeneous regions or structural domains in jointed rock mass. However, only few studies have been conducted by integrating both of them. In this study, by considering the factors of joint occurrence and trace length, a novel method is developed for dividing the statistical homogeneous area of jointed rock mass, which is known as the Wilcoxon rank sum test. It is used to evaluate the degree of the similarity between two samples 0nd then to realize the division of this region. Based on the data of occurrence and trace length of rock mass from four adits at two levels of the left abutment of Maji hydropower station in Yunnan province, the proposed method is applied to statistically identify different homogeneous domains, and to analyze the influence of multi parameters of jointed rock mass on a statistical homogeneous division. The results indicate that, the rock masses within the adits of PD241 and PD253, PD201 and PD241 are incorporated into a statistical homogeneous area, respectively, but those of PD201 and PD251, PD251 and PD253 are situated at different structural domains. Compared to Miller method, the results obtained by the proposed method are more likely to be reasonable and reliable. In comparison with field investigation, it is found that the results from the new method are more agreement with the actual situation.