Study On Stability Control Of Roadway Surrounding Rock Under Near Coal Seam Working Face

For close-distance coal seam mining,the mining activities of the upper coal seam will affect the stability of the roadway surrounding rock of the lower coal seam to a certain degree,and in serious cases,it will lead to the blockage of the lower coal seam mining and affect the normal and safe mining of coal.According to the actual mine situation of the mine,a reasonable roadway support method is selected to control the surrounding rock stability in lower coal seam stoping and maintain the safe and efficient of the mine.Therefore,this thesis takes coal seams A3 and A2 which belongs to close-distance coal seam mining in west well of the Qiuci coal mine in Kuqa,Xinjiang as engineering background,the layout of the upper and lower chute roadway of A201 was analyzed,and the support mode of the lower coal seam mining of A201was investigated by theoretical calculation,engineering example and numerical simulation to realize the safe and efficient production of the mine.The main achievements are as follows:(1)Based on the working face characteristics of the west shaft of the Qiuci coal mine,the mine pressure evolution and the roadway deformation law in working faces A501 and A302,which are typical coal close seam mining with interaction,were analyzed.Of which,the mining of the close coal seam significantly affects the stability of the roadway surrounding rock of the adjacent coal seam,and the deformation of the roadway surrounding rock of the lower coal seam is larger.(2)Based on FLAC^3D numerical simulation,the influence of the upper coal seam mining on the adjacent lower coal seam retrieval roadway is analyzed,providing a theoretical basis for the digging timing of near lower coal seam retrieval roadway.The results show that when the roadway is arranged as inner staggered arrangement and with a inner staggered distance of 20m,the roadway is in low stress area,and the roadway surrounding rock is stable and easy to support.(3)Based on the numerical simulation of the support effect in the retrieval stage of working face A303,the stress distribution law,roadway deformation characteristics and plastic zone development characteristics of the upper and lower chutes of working face A201 under support scheme are obtained,and the best retrieval roadway support scheme is optimized.(4)The on-site monitoring data of mine pressure and roadway surrounding rock deformation show that the growth of surrounding pressure and the rock deformation around the roadway is small,which indicates that the roadway layout plan and support plan maintain the stability of the roadway well.