Analysis of Rock Deformation Evolution and Failure Mechanism Under Different Pre-Fabricated Fracture Dip Angles

To study the influence of different inclination angles (expressed as β) of prefabricated fractures on the evolution of rock deformation and its failure mechanism, the stress-strain curve of basalt was first obtained through laboratory tests; uniaxial compression tests were simulated using the particle flow method (PFC), the evolution process of rock deformation and microcracking was then analyzed, and the initiation mode and of microcracks was determined. The results show that the deformation of peak stress deformation reaches a minimum when β = 15° and 30°, and a maximum when β = 90°; with the increasing β, the proportion of tensile microcracks gradually decreases. In the early stage of crack development, when β is approximately 0°-75°, there are evident weak force chain areas on both sides of the prefabricated fracture. With an increase in β, the influence of the prefabricated fracture on the initiation mode of rock failure is gradually reduced, the strength of the force chain around prefabricated fractures increases, and different modes in the failure process of specimens can be sub-divided.