Investigating the influence of compressive strength on energy release and instability mechanisms of modeled rock-like models containing prefabricated fissures based on AE and DIC technology

Rock fracture is a process of energy accumulation and subsequent release, in which rock mass strength significantly influences this process. This study investigates the energy release and evolution of failure mechanisms in models with different compressive strengths through uniaxial compression tests, acoustic emission techniques, and digital image correlation. The experimental results indicate that during the yielding stage, there is a notable increase in the number of small-scale failures in the models. The failure of the models, initially dominated by shear failure, progressively involves more tensile cracks. Before global instability occurs, significant horizontal relative displacement and localized surface deformation are observed at the pre-existing fissures. As the strength decreases, the models tend to exhibit a larger number of small-scale failures, and the failure mechanism shifts toward a composite shear-tensile mode.