Improvement of Reinforcement Performance and Engineering Application of Small Coal Pillars Arranged in Double Roadways

The supporting technology of retaining small coal pillars in a double roadway layout can effectively relieve the tension of mining and excavation replacement and improve the coal recovery rate. The critical difficulty is that the supporting structure on both sides of the small coal pillar has not established an effective mechanical connection, and the improvement of the bearing capacity of the coal pillar is limited, so it is difficult to achieve long-term stability control of the small coal pillar. Taking the 301 and 302 working faces of Gaojiapu Coal Mine as the engineering background, this paper first constructs the overburden structure model of the whole process of mining with small coal pillars in a double roadway layout, obtains the load calculation and strength calculation methods of small coal pillars through the analysis of the mechanism of small coal pillars surrounding rock mechanics, and gives the selection design of support parameters of anchor cables and concrete filled steel tubular piers; Secondly, the influence rules of physical and mechanical parameters such as axial load, elastic modulus and residual strength of anchor solid under different reinforcement methods and the lateral reinforcement coefficient of anchor cable are obtained through experiments. Finally, the support parameters and the coal pillar width are reasonably designed. The field monitoring data show that the reinforcement technology of a small coal pillar with anchor cable as the main body can effectively control the deformation of the small coal pillar, which has specific guiding significance and application value for solving the long-term stability control problem of small coal pillar under the influence of mining.