An exploration of improving the stability of mining roadways constructed in soft rock by roof cutting and stress transfer: A case study

Abstract

In the confinement of traditional supports, reinforced supports are often used to control the deformation of roadways constructed in soft rock. Due to the failure to weaken the factors that induce deformation at the source, the roadway remains damaged after the restoration period. To this end, taking inspiration from roof cutting and pressure relief concepts, the protection mechanism of stress transfer in mining roadways constructed in soft rock of longwall remaining coal pillars was studied in the context of a typical coal mine. Unlike the technical scheme of gob-side entry retaining, no components are added in this study. The roof cutting and coal mining progress are consistent to ensure the integrity of the roadway in front of the longwall coal mining face (LCMF). The effect of the roof-cutting parameter on the roadway is studied via numerical simulations, and the optimal parameters are subsequently applied to similar material simulation experiments. It was found that roof cutting relieved the mechanical connection between the gob roof and the roadway roof, and the high-stress area was transferred from the roadway roof to the front of the LCMF. Roof cutting diminished the abutment stress in the surrounding rock in the area of intense dynamic pressure in front of the LCMF (average reduction of 12.57 %), which effectively improved the stability of the roadway. The roof cutting impaired the traction effect of the roadway roof deformation behind the LCMF on the strata ahead and effectively reduced the roadway deformation (27.3 % reduction) and coal pillar deformation (15.7 % reduction). On-site practice has demonstrated the effectiveness of this research, and the results of this research provide a new idea for preventing the destruction of roadways constructed in soft rock.