关键词: 高应力煤体, 小煤柱护巷, 水力压裂, 围岩稳定性, 钻场充填

Abstract: The small coal pillar roadway in the high stress environment was faced with the problems of poor stability of surrounding rock and difficult maintenance of roadway. Using laboratory experiments, field experiments and engineering practices, taking the application site of 5 m small coal pillar in 15 # coal seam of Fuda Coal mine as the background, aiming at the key factors affecting the stability of surrounding rock of small coal pillar roadway, including high in-situ stress level, poor stability of surrounding rock and drilling field goaf left in coal pillar, the technical scheme of lateral hydraulic fracturing pressure relief, stability control of surrounding rock of empty roadway and high water material filling in hidden drilling field in coal pillar is put forward, and field application is carried out. The results show that : ( 1 ) The peak initiation pressure of the key layers of hydraulic fracturing is 26.5 MPa, and the average maximum pressure of each hole is 22.3 MPa. The primary cracks in the hole are gradually opened by the extrusion of high-pressure water, which weakens the integrity of the roof significantly. ( 2 ) Based on the analysis of roadway mine pressure data, the peak stress of roof bolt is 108 kN, and the peak stress of side bolt is 86 kN, which are far lower than the yield load of bolt, and there is no anchor breaking phenomenon. The subsidence of the two sides and roof of the roadway is within the controllable range, the shrinkage of the roadway is small, and the overall stability of the surrounding rock is effectively controlled. ( 3 ) The total volume of filling high-water materials in the hidden drilling field is 682.9m3, which is higher than the total volume of the empty area of the drilling field. Each filling borehole ensures that the grouting is stopped after the slurry is returned. The filling rate of the drilling field is high, and the stability of the residual 1.5m coal pillar is good.