Damage Process and Fracture Mechanisms in the Rock Surrounding a Roadway Caused by Blasting-Induced Disturbance under High Stress

Abstract

The aim of this study is to investigate damage processes and fracture mechanisms in the rock surrounding a roadway under blasting-induced disturbance in a high-stress environment. A disturbance test involving blasting of the rock surrounding a roadway under different lateral pressure coefficients was conducted using high-precision acoustic emission (AE) monitoring. Based thereon, the spatiotemporal evolution and cluster characteristics of microcracks in the surrounding rock of the roadway under dynamic disturbance induced by explosive blasting were obtained, and stress transfer, adjustment, and redistribution in the rock mass were revealed. Moreover, a method for describing the progressive damage to the rock mass was established. The conclusions were as follows: the high-stress environment was conducive to microcrack initiation and propagation in the specimens, and the failure patterns of the surrounding rock of the roadway under different lateral pressure coefficients differed. The direction of crack propagation in the rock surrounding the roadway is opposite to that of the maximum principal stress applied to the rock mass. Blasting-induced disturbance intensifies crack initiation and accelerates damage accumulation and macrofracture formation in the rock mass. The macroscopic failure zone in a model is correlated with the ultimate distribution of apparent stress, and the apparent stress can reflect the adjustment of the stress field therein. The damage variable, characterized by the ratio of the number of AE events, can reveal the evolution of damage in the rock surrounding a roadway.