Precise gas control technology for fault fracture zones in deep roadways

To address the challenge of abnormal gas outflow in fault fracture zones during deep coal mine roadway excavation, this study proposes a precise gas control technology based on integrated detection and dual-interception strategies, using the 221 East Wing Track Roadway of Shanxi Liujialiang Coal Mine as the engineering case. Fast Lagrangian Analysis of Continua (FLAC3D) was employed to determine the roadway surrounding rock loosened zone (0.45–2.3 m), establishing a theoretical foundation for optimizing borehole layout design. By synergistically integrating the transient electromagnetic method with geological drilling, the study characterized the gas-enriched zones and fissure water distribution patterns ahead of the excavation face. An innovative “inner barrier + outer interception” dual-control system is proposed: outer high-negative-pressure boreholes (≥3.0 m from roadway contour) block gas supply channels, while inner low-negative-pressure boreholes (≥2.0 m from roadway contour) establish gas–water composite barriers. Field applications demonstrate that gradient borehole spacing and coordinated negative-pressure control reduce extraction workload by 30% compared to traditional methods. Post-blasting gas concentrations recover from 0.28% to the minimum value (0.02%) within 2–4 min, excavation efficiency increases by 25%, and boreholes outside the loosening zone avoid air infiltration. This technology establishes a high-efficiency, low-cost pathway for gas control in complex geological conditions, offering significant potential for ensuring safe and rapid roadway excavation in deep high-gas mines. The technology provides new ideas for gas management in deep mines.