Mechanisms of Roadway Instability and Coupled Control Technology for Working Face Passing Through Fault Zones

To investigate the mechanisms of rock mass instability and control challenges in roadway sections crossing fault zones, this study uses the longwall mining roadway in the 5 1 104 working face of the Shengxin Coal Mine as its engineering context. Methods such as theoretical analysis, borehole inspection, and numerical simulation were employed to determine the mechanism of rock mass instability in the roadway section crossing the fault zone. Borehole inspection revealed that fractures of varying depths and strike directions developed at approximately 3.2 m to 4.5 m on the left rib, 2.8 m to 3.5 m on the right rib, and around 4.9 m at the roof, forming a complete failure zone; Numerical simulations analyzed the stress distribution in the surrounding rock after roadway excavation, confirming that the plastic zone of the surrounding rock exhibits a symmetrical distribution, with failure extending 4.5 m along both sides and 6 m at the roof; When the working face advances to a certain position, stress peaks of 6.5 MPa are observed at locations 10 m to 60 m ahead of the face, confirming that the roof and both sides of the roadway surrounding rock are critical areas for support control; Based on borehole inspection and numerical simulation results, a comprehensive coupled support technology scheme was proposed, combining high‐ and low‐pressure grouting using deep and shallow boreholes with high‐preload anchor cables; Engineering tests verified that after implementing this technology, the cumulative displacement of the sidewalls was 170 mm, the cumulative subsidence of the roadway roof stabilized at 151 mm, the cumulative heave of the roadway floor was 130 mm, and the total deformation rate remained at a low level of 0.2–0.3 mm/month. Consequently, this coupled support scheme effectively maintained the surrounding rock in a stable state, with no instances of support failure or abnormal mining pressure phenomena such as rib collapse, thereby validating the rationality of the surrounding rock control technology.