Demarcation of Structural Domains in Fractured Rock Masses Using a Three‐Parameter Simultaneous Analysis Method

Abstract

A structural domain represents a volume of a rock mass with similar mechanical and hydrological properties. To demarcate structural domains (or statistically homogeneous regions) in fractured rock masses, this study proposes a three-parameter simultaneous analysis method (3PSAM) that simultaneously considers rock fracture orientation, trace length, and aperture to evaluate statistical homogeneity between two regions. First, a 102-patch three-dimensional Schmidt net, which represents a new comprehensive classification system, is established to characterize rock fractures based on their orientation and aperture. Two populations of rock fractures can then be projected to the corresponding patches. Second, the Wald–Wolfowitz runs test is used to measure the similarity between the two populations by considering the fracture trace lengths. The results obtained by applying the 3PSAM to seven simulated fracture populations show that the homogeneity is influenced by both the distributions of the fracture parameters and the sequences of the fracture parameters. The influence of a specific combination sequence makes it impractical to analyze the rock fracture parameters individually. Combined with previous methods, the 3PSAM provides reasonable and accurate results when it is applied to a fractured rock slope engineering case study in Dalian, China. The results show that each fracture population should be identified as an independent structural domain when using the 3PSAM. Only the 3PSAM identifies the west exploratory trench 2 and the east exploratory trench as being nonhomogeneous because the difference in the aperture of the two fracture populations is considered. The benefit of the 3PSAM is that it simultaneously considers three parameters in the demarcation of structural domains.

A cluster-based multiparametric similarity test for the compartmentalization of crystalline rocks into structural domains

“…Because of the enumerated limitations and that orientation is the only fracture parameter that Miller (1983) used, several researchers have proposed variants of his method. These variants involved other equal area subdivision patches of the stereonet (QuocPhi et al 2012;Song et al 2015), other fracture parameters (Li et al, 2015;Song et al, 2015Song et al, , 2018; Zhang et al, 2016;Zhou et al, 2018), or other statistical tests (Martin and Tannant 2004;Li et al 2014aLi et al , 2015Song et al 2015Song et al , 2018. In the literature, it was noted that Miller's test and its variants were mainly used in engineering studies, which did not exceed a few square kilometers.…”

“…Although using two hypothesis tests increase the confidence of the similarity between clusters, as the result of one hypothesis test is verified by the other, the choice of using one or two hypothesis tests is left under the appreciation of the practitioner. It is a common practice in engineering geology to use one hypothesis test (Miller 1983;Song et al 2015;Zhou et al 2018) or two hypothesis tests (Li et al 2014b;Zhang et al 2016) in analysis of similarities between data sets. Arguably, choosing the right hypothesis test is much more important than the number of utilized hypothesis tests.…”

Engineering Classification of Jointed Rock Mass Based on Connectional Expectation: A Case Study for Songta Dam Site, China

“…Jointed rock mass quality is mainly affected by its own structural characteristics (integrity, rock strength, weathering degree, etc.) and its surrounding environment (in situ stress and groundwater), which can generally reflect the engineering geological properties of rock mass within a certain spatial extent [1][2][3]. erefore, the classification of rock mass quality should be based on the above influencing factors, and specific indexes should be used to evaluate rock mass properties by qualitative or quantitative methods.…”