Deformation Mechanisms and Coordinated Support–Relief Control of Deep Roadways Under Multi-Dynamic Pressure Conditions

To address the pronounced asymmetric deformation of roadway-surrounding rock under deep multi-dynamic pressure, the N8003 tailgate of the Wuyang Mine was adopted as the engineering background, and the deformation–failure characteristics of the roadway sidewalls and the evolution of deviatoric stress under dynamic loading were analyzed. Based on numerical simulation, the maximum principal deviatoric stress S1 was employed as the core indicator for evaluating pressure-relief effectiveness, upon which a three–dimensional Pressure Relief Efficiency Index (PREI) considering strength, range, and position was developed. The key parameters of large-diameter hydraulic cavitation pressure–relief boreholes were optimized, and the evolution patterns of deviatoric stress under static and dynamic conditions were further revealed. To overcome the limitations of conventional high-strength bolt–cable combined support in controlling large deformation, a layered support–relief collaborative control technology featuring “external reinforcement fixation (ERF), near-surface modification and grouting (NSMG), and deep targeted destressing (DTD)” was proposed. Field tests demonstrated that this technology can significantly suppress sidewall deformation, maintain support system stability, and exhibit strong adaptability and application potential in deep roadways influenced by multi-dynamic pressure.