Abstract:
In order to investigate the application effect of roof-cutting and pressure relief gob-side entry returning technology in shallow buried deep and medium-thickness coal seam, combining theoretical analysis, numerical simulation, on-site monitoring and other means, we carried out study on the key technical parameters of shallow buried deep and medium-thickness coal seam roof-cutting entry-retaining in the 51112 working face of Jintong Coal Mine.First, the working face and roadway support form was investigated: 51112 working face's average buried depth is 55 m, the thickness of the coal seam is 3.2 m, with the typical shallow buried deep medium-thickness coal seam with soft weak roof, and the roadway deformation characteristics of the surrounding rock was analyzed; the key technologies-related parameters of roof cutting slit, cumulative energy blasting, constant resistance anchor cable support, blocking gangue support, and racking temporary support were designed, and optimum parameters were determined; then the optimal slit height of 9 m was confirmed through the numerical simulation of different slit heights, and the optimal slit angle of 15° was confirmed through the numerical simulation of different slit angles, and then the designed technical parameters of the retaining roadway were applied in the field.The on-site monitoring results show that the pressure relief effect of the working face is obvious, the final convergence of the roof and floor of the entry retaining is 233 mm, and the convergence of the two sides is 150 mm, the deformation of the surrounding rock is controllable, the effect of the roadway formation is remarkable, and the effective section size is enough to meet the reuse requirements of the adjacent working face.