Optimization Research on Coal Pillar Width in Roadway Excavation Along Goaf of Deep Thick Coal Seam

Aiming at the large width of remaining coal pillars in the deep thick coal seam working face, the existing problems of large deformation, difficult support, and low recovery rate in the roadway excavation along goaf of the working face in Guotun Coal Mine, taking the 2303 working face tape crossheading roadway excavation along goaf of Guotun Coal Mine as the research background, through methods of theoretical analysis, numerical simulation and others, a support pressure model for the roadway along goaf is established. The distribution law of the stoping support pressure in the upper section and the internal stress law of the coal pillar are analyzed, and the influence relationship of narrow coal pillar width on the stability of the surrounding rock of the roadway along goaf is obtained. The theoretical calculation shows that the coal pillar width is 4.97-5.73 m, and the numerical simulation verifies that 5 m is the optimal solution. The on-site industrial testing results show that by adopting the anchor net cable support way in the roadway along goaf, the remaining width of the coal pillar is reduced to 5 m, the maximum subsidence amount of the roadway roof after roadway excavation is 32.1 mm, the maximum deformation amount of the two sides is 60.3 mm, and the stability of the roadway surrounding rock is good.