关键词: 大采高工作面, 特厚煤层, 爆破切顶卸压, 数值模拟, 现场试验

Abstract: Aiming at the large deformation of the roadway that still occurs with the 5210 working face under the condition of high-strength support in the 5209 return airway of Madaotou Coal Mine, theoretical analysis, numerical simulation, field experiments and other methods are used to conduct underground directional blasting for large mining heights and thicknesses. The technology of roof cut and pressure relief by directional blasting in roof roadway has been studied. The research results show that the working principle of roadway blasting and top-cutting pressure relief is to blast and top-cut the basic top rock layer on the side of the coal pillar to make it collapse in time, reduce the load of the coal pillar and the basic top rock layer due to the rotation and sinking. The load on the coal pillar; the basic top rock strata is reduced in both the initial collapse step and the periodic collapse step after the roof is cut and relieved, thereby reducing the appearance of the rock pressure; the best cutting angle for the blasting and pressure relief is at 60°, after blasting and cutting the top and releasing the pressure, the peak stress decreased from 21.1 MPa to 16.3 MPa; after the blasting, the drilling and peeping results showed that the blasting hole and the pilot hole produced a gap with the direction along the direction of the energy-concentrating tube in the hole Cracks in the same direction; observation of the surface displacement of the roadway in the 5209 return airway revealed that the overall deformation is small and the roadway integrity is good, indicating that the directional blasting has a significant effect of top-cutting and decompression.