Evaluation of statistical homogeneity of jointed rock masses based on weighted least-square method

The identification of structural homogeneity has been an important topic in the field of geotechnical engineering. Most of scholars use joint orientations or the other joint parameters to identify statistically homogeneous regions or structural domains in a jointed rock mass. However, few studies have been conducted by integrating both of them. Five parameters are considered for this identification, namely: joint orientation, spacing, aperture, trace length and roughness. Based on the weighted least-square method, the weights of the parameters are obtained. A statistical parameter, known as the correlation coefficient, is used to quantify the degree of the similarity between the joint parameters collected from the studied regions. The overall homogeneity of the rock mass is determined based on the homogeneity index. A practical engineering case is analyzed, illustrating the effect of the multiple parameters collected from four adjacent adits at Maji dam site on the left bank of the Nujiang River in Yunnan Province on identification of statistical homogeneity in fractured rock mass. The results indicate that the identification of statistical homogeneity is influenced by many factors such as the joint orientations, spacing, aperture, trace length and roughness. The statistical homogeneous domains in the studied regions are successfully divided, indicating the feasibility of the proposed method.