Anisotropy of Surface Morphology Characteristics of Rock Discontinuity and Its Evaluation Method

Abstract

The mechanical and hydraulic properties of rock discontinuity are anisotropic, and the main reason resides in the anisotropy of surface morphology. This study delved systematically into the anisotropic characteristics of surface morphology and its evaluation method. Among hundreds of morphology parameters, the most representative one was selected utilizing mathematical statistics and correlation analysis. Through morphology analysis of eight discontinuity specimens, the maximum deviation of roughness in each direction was proposed as an anisotropy evaluation index, serving as a bridge to establish the relationship between the anisotropic characteristics of surface morphology and shear strength. In-depth research was conducted to discuss the distribution range of controlling factors of shear strength and explore the influence of anisotropy degree and controlling factors on the prediction deviation of shear strength. Based on the aforementioned results, an anisotropy evaluation method was put forth to divide the anisotropy degree of rock discontinuity into four levels, and the prediction deviation of shear strength at each level was described in a quantitative manner. The novelty of this study is listed as follows. The existing literature lacks research on quantitative evaluation methods of anisotropic characteristics, and this study would compensate for this deficiency; this method has a valid theoretical foundation and is capable of simultaneously determining the anisotropic characteristics of morphology and shear strength; the methods concerning how to simplify surface morphology as isotropy and embed discontinuity roughness into a numerical algorithm have been proposed, respectively. These findings would provide theoretical support for the deformation control and stability analysis of rock mass in engineering.