Fracture mechanisms of intact rock-like materials under compression

The fracture mechanism in natural rock is closely related to the nucleation and interaction of microcracks. However, a comprehensive understanding of the crack evolution in intact rocks remains unclear. This paper presents a systematic investigation on the microcrack nucleation, coalescence and propagation in conjunction with detailed characterization of local stress distribution and bond strength information by means of the discrete element-based modelling. It was found that crack initiation dominates at the elastic stage and crack coalescence takes control at the unstable crack growth stage. Crack growth in both the stages is sensitive to the local heterogeneity of the sample and local stress distribution. In the post-peak regime, crack growth becomes intensified and localised, forming the shear zone and leading to a complete disintegration of a sample.