基于顶板耦合的厚煤层开采初次来压步距研究OA

To reveal the formation mechanism of the first weighting step distance during deep and thick coal seam mining,this study took a thick coal seam working face in the Huaibei mining area as the engineering background.Based on fracture mechanics and the thin plate bending theory,a coupled double-layer thin-plate model of the immediate roof-main roof system was established.Moreover,the concept of interlayer coupling stiffness was introduced to characterize the coordinated deformation behavior between the two rock strata,and analytical expressions for the first weighting step distance were derived under both strong and weak coupling conditions.A three-dimensional discrete element model was further constructed with the aid of 3DEC software,and a parameter sensitivity analysis was performed considering the thickness and elastic modulus of both the immediate and main roofs.The results indicate that with the increase in interlayer coupling stiffness,immediate roof thickness,and main roof thickness,the overall flexural stiffness of the roof structure improves,energy release is delayed,and the first weighting step distance significantly enlarges.Field monitoring of the thick coal seam working face shows that the measured first weighting step distance is 25.6 m,which agrees well with the theoretical value of 26.7 m and the numerical result of 26 m.The findings provide a theoretical basis and technical reference for the analysis on roof stability and ground pressure control in deep and thick coal seam mining.