Reasonable value range of damage stress during rock brittle failure under compression

Abstract

It is significant to clarify the reasonable value range of damage stress in the brittle failure process of rock to predict rock instability, such as collapse and landslide. Previous studies on damage stress were mostly limited to the statistical analysis of results obtained through laboratory rock mechanics experiments, and relevant theoretical studies are urgently needed. This study first derived the theoretical expression of the ratio of the rock damage stress to the peak stress σcd/σf by combining the three dimensional renormalization group model established by the proper stress transfer mechanism with the rock damage constitutive model, and obtained its theoretical range. Then, the rationality of the theoretical results was tested by analyzing the statistical results obtained through laboratory rock mechanics experiments for samples with different lithologies under different confining pressures. The reasonable value range of σcd/σf for describing the brittle failure of rock under compression is [0.76, 0.93]. The reasons for some experimentally obtained σcd/σf values falling outside of the reasonable range are discussed. The findings of this study can be useful for the investigation of disaster mechanisms and the development of rock mass instability prediction models.