中厚煤层切顶卸压自成巷技术研究OA

In view of the problems of surrounding rock stress concentration,large deformation,severe loss of coal pillar resources and others in retaining roadway along goaf under the condition of medium thick coal seam composite roof,taking the 4306 working face of Hexi Coal Mine as the engineering background,the on-site application effect of roof cutting and pressure relief self-formed roadway without coal pillar(110 working method)is systematically studied.Based on the lithology structure and mechanical parameters of the roof,a bidirectional energy gathering pre-splitting and joint-cutting scheme is designed,and a collaborative support system is constructed by combining NPR constant resistance large deformation anchor cable.The roof stress,roadway deformation,and force-bearing characteristics of the support are quantitatively analyzed through on-site monitoring means.The results show that when the roof cutting height is set to 10 m,the NPR anchor cable constant resistance is 300 kN,and when the maximum allowable deformation amount is 1200 mm,the maximum subsidence amount of the retaining roadway roof is controlled within 180 mm,the convergence amount of the two sides is less than 260 mm,the working resistance of the bracket is reduced by about 20%to 25%compared to the traditional working method,and the overall stability of the roadway is significantly improved.The research results provide reference for the engineering application of roof cutting and pressure relief self-forming roadway technology under conditions with similar medium thick coal seams.