Research on Collaborative Control Technology of Pressure Relief and Support for Retaining Roadway along Goaf with Hard Roof

Abstract

According to field observation of the deformation of the reserved roadway with a hard roof, the shrinkage of the roof and floor on the goaf side is greater than on the coal side, and the surrounding rock of the road is in a long-term rheological deformation state. Through theoretical analysis, the relationship between the tensile stress of the rock and the top cutting and pressure relief parameters is expounded. In a certain range, with increasing cutting height and cutting angle, the tensile stress of the hard rock strata without top cutting is also greater, which is conducive to caving the roof. Through numerical simulation analysis, when the cutting height and cutting angle are 7m and 15 °, respectively, the deformation and stress of the surrounding rock are small and tend to be stable. Combined with theoretical calculation and construction cost, this parameter is determined to be the best top cutting parameter. Based on the failure causes of the retaining road along the hard roof and the need for strengthening support of the roof, the synergistic surrounding rock control technology of pressure relief and support is proposed. After adopting the surrounding rock control technology of roof cutting and pressure relief + constant resistance large deformation anchor cable of constant resistance support, the maximum deformation of the roof and floor of the reserved roadway is reduced from 750mm to 322 mm, and the maximum deformation of the solid coal is reduced from 486mm to 205mm. The surrounding rock control effect is good. The successful application of this technology improves the recovery rate of 090109 working face in Baigou Coal Mine and realizes the sustainable development and utilization of coal resources. It also provides guidance and reference for the control of surrounding rocks with similar roof conditions.