Study on Macro-Meso Failure Mechanism of Pre-fractured Rock Specimens Under Uniaxial Compression

There are many fractures in natural rock mass which have a significant influence on the stability of rock engineering. Rock is a kind of aggregate made up of various particles, the research on the meso level can fundamentally reveal the failure mechanism. In order to comprehensively research the effect mechanism of fractures on the failure characteristics of fractured rock, uniaxial compression numerical experiments were conducted based on discrete element method. The macroscopic and mesoscopic mechanical response of pre-fractured rock specimens with varying fracture length and dip angle were studied. The evolution process of macroscopic and mesoscopic physical quantities was obtained. The results show that the macroscopic failure process of fractured rock was an evolution process of rock from the microscopic level to macroscopic level that resulted from the interaction of internal particles under compression loading. In this process, the energy dissipation was also evolving. There was an obvious relativity between the particle rotation radian region-related feature and the distribution location and number features of cracks. The distribution pattern of prefabricated fractures had a great influence on the failure mode and plays an important role in the macroscopic characteristics and the evolution of internal components of pre-fractured rock specimens. Research result is full of important theory significance and engineering value to evaluate the stability of rock engineering.