Control Countermeasures of Surrounding Rock in Deep Gob-side Entry Retaining by Cutting Roof
摘要
Based on the technical principle of gob-side entry retaining formed by advanced roof cutting, this study takes non-pillar mining in deep working face of Chengjiao coal mine as the research background, and comprehensively uses methods of mechanics analysis, numerical calculation and field measurement to investigate the control countermeasures of surrounding rock in deep gob-side entry retaining formed by cutting roof. The roof of gob-side entry retaining induced by cutting roof formed a cantilever beam above the roadway and the pressure on the roadside support body was reduced. The broken expand gangue formed by cutting the roof filled the goaf good, which reduced the displacement of roof sinking by about 50%. It should be noted that the side roof of gob area is the key part for surrounding rock deformation in roof cutting roadway and needs to be intensively supported. Note that the plastic zone of solid coal rib in deep roof cutting roadway is large and the shallow bolt bearing layer can be anchored in the stable coal body in the elastic zone using the anchor coal rib support technology. The pressure of deep roof cutting roadway has a fast speed and is very fierce after mining, leading to the damage of single prop in the roadway. Utilizing the hydraulic supporter with high resistance as the temporary support can resist deep strong dynamic pressure and the impact load. The roadside rigid block gangue experienced compression bending failure due to its inability to adapt to the large deformation. In order to have consistent deformation with the roof and floor, the roadside block gangue in deep roof cutting roadway should achieve a certain vertical sliding deformation. The support technology combining gob-side roof constant resistance large deformation bolt, contractible U section steel block gangue, entry-in hydraulic support and solid coal side anchor rope was proposed, and the industrial field tests were conducted. The field monitoring results show that the surroundi