In the study of rock dynamic mechanical behavior,rock crack propagation model reveals the crack propagation process of rock materials under dynamic loads theoretically,and provides theoretical support for the failure law of rock materials under dynamic loads. Rock fracture toughness can be used to characterize the fracture resistance of rock materials or the resistance to produce new cracks.Especially when there are a few main cracks acting on rock materials,fracture toughness can predict fracture failure of rock materials more effectively than other strength parameters.However,stress intensit...