Stability control measures for roof cutting and NPR supporting of mining roadways in fault areas of kilometre-deep coal mine

The study focuses on the stability control measures for mining roadways in fault zones of deep mines, using Daqiang Coal Mine as a case study. The control system under consideration, referred to as “pre-splitting cutting roof + NPR anchor cable” (PSCR-NPR), is subjected to scrutiny through theoretical analysis, numerical modelling, and field trials. Furthermore, a comprehensive analysis is undertaken to evaluate the stability control mechanism of this particular technology. The study provides evidence that the utilization of deep-hole directional energy-concentrated blasting facilitates the attainment of directional roof cutting in roadways. The aforementioned procedure leads to the formation of a uniform structural surface on the roof of the roadway and causes modifications in the surrounding geological formation. The examination of the lateral abutment pressure and shear stress distribution, both prior to and subsequent to roof cutting, indicates that the implementation of pre-splitting techniques leads to a noteworthy reduction in pressure. The proposition of incorporating the safety factor Q for roof cutting height is suggested as a method to augment comprehension of the pressure relief phenomenon in the field of engineering. The analysis of numerical simulation has indicated that the optimal pressure relief effect of a mining roadway in a fault area is attained when the value of Q is 1.8. The NPR anchor cable exhibits noteworthy characteristics, including a high level of prestress, continuous resistance, and substantial deformation. After the excavation of the roadway, a notable reduction in radial stress occurs, leading to the reinstatement of the three-phase stress state in the surrounding rock. This restoration is attributed to the substantial prestress exerted on the radial stress. The termination point of the NPR anchor cable is strategically positioned within a stable rock formation, allowing for the utilization of the mechanical characteristics of the deep stable rock mass. This positioning serves to improve the load-bearing capacity of the surrounding rock. The mining roadway within the fault region of Daqiang Coal Mine is outfitted with the PSCR-NPR technology. The drop in shear stress experienced by the rock surrounding the roadway is estimated to be around 30%, whilst the low-stress region of the mining roadway extends by a factor of approximately 5.5. The magnitude of surface displacement convergence experiences a decrease of approximately 45%–50%. The study’s findings provide useful insights regarding the stable of mining roadway in characterized by fault zones.