Study on Deformation and Failure Characteristics of Surrounding Rock and Supporting Countermeasures in Deep Mining Dynamic Pressure Roadways

Deep rock masses have long been in a complex geomechanical environment characterized by "high ground stress, high groundwater pressure, high temperature, and strong disturbance", which complicates their structural characteristics and mechanical behaviors. The − 850m roadway in Qujiang Coal Mine is laid longitudinally under the 805 working face and coal pillars. Affected by the mining activities of the upper working face and the eccentric pressure of coal pillars, the roadway exhibits various deformation and failure characteristics. In this study, field investigations, stress monitoring of bolts and cables, and surrounding rock deformation monitoring were conducted to analyze the deformation and failure patterns of the mining-induced dynamic pressure roadway. Additionally, the FLAC3D numerical software was used to verify and analyze the proposed support countermeasures. The results show that: (1) Through methods such as axial force monitoring of bolts and cables and surrounding rock deformation monitoring, it is found that the − 850m mining-induced dynamic pressure roadway has obvious zonal failure characteristics, which are divided into the rear continuous (high-pressure) deformation zone and the front disturbed (dynamic pressure) deformation zone. (2) In the front disturbed (dynamic pressure) deformation zone, failures mainly occur in the roadway roof, mostly in the form of sliding shear failure. In the rear continuous (high-pressure) deformation zone, failures are mainly concentrated in the floor and arch feet: the floor is prone to plastic extrusion deformation and failure, while the arch feet mainly suffer from punching shear and inward folding failures. (3) Based on the failure patterns of different zones in the − 850m roadway, it is proposed that the "triple-anchor" combined support technology should be applied in the rear continuous (high-pressure) deformation zone, and the support concept of combining resistance and yielding should be adopted in the front disturbed (dynamic pressure) deformation zone. (4) FLAC3D numerical simulation was carried out, and the simulation data were consistent with the field measured data of reinforcement, confirming the rationality and effectiveness of the proposed zonal support countermeasures. The research results provide a certain reference for the surrounding rock deformation control of deep mining-induced dynamic pressure roadways in the future.