Robustness of Rock Damage Regions Induced by Crack Nucleation

Abstract

The stress-induced fracture of brittle rocks, as a result of macrocrack evolution, is closely related to the evolution of microcracks. The study of such damage processes provides information about the mechanical behavior of rock cracks. In this study, we conducted research with respect to macrocracks using hypothetical damage regions constituted by correlated microcracks. A Gaussian mixture model was applied to describe the spatial distribution of microcracks. The Kullback–Leibler divergence was used to characterize the geometric variation of damage regions. The results showed that the robustness of the damage region’s geometry became increasingly higher during the damage evolution and the damage region became unchanged after some time. The robustness of the damage regions could be an indicator of the nucleation of macrocracks. Moreover, a fracture nucleation indicator methodology was developed to calculate the point at which nucleation was formed. This study is considered to enhance the understanding of macrocrack nucleation and it is useful to the application of macrocrack recognition and prediction.