Deformation, Failure Mechanism and Control Technology of Soft Rock Roadways Buried Under Coal Pillars: A Case Study

Close-distance coal seam mining in Danhou coal mine has caused serious deformation in the underlying soft rock roadways. The mechanism of this type of deformation is explored through theoretical analysis and numerical simulation, and corresponding control measures are proposed. Firstly, the mechanical model of abutment stress transfer along the underlying rock stratum is established, and the analytical solution of abutment stress at any point of the underlying rock stratum is derived. Secondly, the impact of upper working face mining on the underlying soft rock roadway is investigated through numerical simulation. Subsequently, the stress distribution characteristics of the surrounding rock of the rectangular roadway and straight- wall arch roadway are compared and analyzed. Finally, a support scheme for the underlying soft rock roadway is presented and implemented in engineering practice. Field engineering application results demonstrate that, after the combined support of high-strength bolts and grouting, the average deformation on both sides of the roadway is reduced by 63.4%, and the average floor heave is decreased by 93%. This indicates that the technology effectively controls the deformation of the surrounding rock in soft rock roadways during close-distance coal seam mining.