Mechanical Behavior and Fracture Characteristics of Rock with Prefabricated Crack under Different Triaxial Stress Conditions

In this study, the compression failure test of rock with prefabricated fractures under different true triaxial conditions is carried out by using the true triaxial electro-hydraulic servo test system. The traditional large number of fracture laws with prefabricated fissures are merged and attributed to the induction of intermediate principal stress. The test results show that the direction of sigma(2) has a significant effect on the deformation characteristics of the prefabricated fractured rock. The internal crack expansion direction is more random and the crack distribution is more extensive and complex under uniaxial and conventional triaxial conditions. Under biaxial and true triaxial conditions, the crack propagation direction is clearly along the sigma(2) direction. This shows that the development process of internal cracks in rocks tend to the direction of sigma(2). Further, the failure mechanism of rock with prefabricated cracks is analyzed based on theory. It is found that the intermediate principal stress direction plays a very important role in inducing the direction of rock crack propagation. According to the unified idea, the fracture analysis of fractured rock is summed up as true triaxial theory, and the results are consistent with the experimental results. This provides a new perspective for the study of rock fracture mechanics, and provides an important basis for the analysis of surrounding rock fracture mechanism of underground engineering.