关键词: 缓倾斜煤层, 半煤岩巷道, 沿空掘巷, 煤柱, 围岩控制

Abstract: Aiming at the engineering problems of coal pillar shear slip，asymmetric large deformation of roadway side and difficult support of surrounding rock in the gob-side entry of semi-coal rock in gently inclined coal seam under the action of multiple mining disturbances，taking the II7226S air roadway of Ren⁃ lou Coal Mine as the engineering background，the research methods of theoretical analysis，numerical sim⁃ ulation and field industrial test are combined. Based on the internal and external stress field theory and lim⁃ it equilibrium theory，the reasonable interval of section coal pillar is solved. The stress，displacement and plastic zone evolution characteristics of roadway surrounding rock under different coal pillar widths are compared and analyzed by multiple sets of numerical models，and the optimal size of coal pillar for road⁃ way protection is determined and the corresponding surrounding rock control technology is matched. The re⁃ sults show that the difference of mechanical strength between coal and rock and the weak structure effect of coal-rock interface are the core causes of asymmetric deformation of roadway. The upper coal seam on the side of small coal pillar is prone to shear extrusion failure along the coal-rock interface，which is the key part of surrounding rock control. The theoretical calculation shows that the reasonable interval of coal pillar is 4.6~6.1 m. The comprehensive simulation results show that the optimal width of coal pillar is 5 m. This size can effectively avoid the influence of the peak value of lateral abutment pressure in the upper goaf. The roadway and roof surrounding rock can retain a large range of elastic bearing core area，and the deforma⁃ tion of surrounding rock is significantly controlled. In view of the instability characteristics of this kind of roadway，this paper proposes a combined control scheme of strengthening support in key parts and grouting modification and reinforcement of broken surrounding rock. The field monitoring results show that the defor⁃ mation of surrounding rock tends to be stable after 40 days of roadway excavation. The maximum deforma⁃ tion of roof，floor，small coal pillar and solid coal is 68.4 mm，30.9 mm，79.1 mm and 53.2 mm respec⁃ tively，and the overall stability of surrounding rock is good. The research results can provide engineering reference for the design of coal pillar parameters and surrounding rock control of semi-coal rock gob-side roadway in gently inclined coal seam of Northern Anhui mining area.