Dynamic Fracture Characteristics of Layered Rock Mass With Two Beddings Under Explosive Loads of Slotted Charges

Abstract

A large number of beddings inside layered rock masses can significantly affect the dynamic fracture characteristics of the rock mass. In this study, the propagation process of explosive cracks in layered rock masses was visualized using digital image correlation combined with high-speed photography technology, focusing on the dynamic fracture mechanical behavior of layered rock masses with two beddings under an explosive load of slotted charges. The results indicate that, in the fracture process of layered rock masses, a large number of microscopic cracks in the front area of the crack tip are continuously activated, developed, and fused, ultimately converging into macroscopic main cracks that can cause fracture failure. During the dynamic fracture process of the layered rock masses, the displacement field of the specimen exhibited a clear gradient, with obvious displacement contour lines appearing and no discontinuity in the contour lines at the beddings. Under the premise of an appropriate spacing between the two beddings, the continuous reflection and superposition of stress waves between the two beddings causes the rock mass to crack again, resulting in secondary cracks. Vertical bedding has an inhibitory effect on the propagation behavior of the main explosive crack.