近距离采空区下回采巷道位置确定及围岩控制技术OA

In Zhangcun Coal Mine,No.2 coal seam and No.2 lower coal seam were defined as close-distance coal seams,and the downward mining method was adopted.To ensure the stability of mining roadways in the No.2 lower coal seam,a research on surrounding rock control technology for mining roadways under close-distance goafs was carried out.Severe mine pressure behavior was exhibited during the excavation of the material transportation roadway in No.2614 Face of No.2 lower coal seam.Large roadway deformation,long deformation duration and damage of bolt support components were observed on site.A mechanical model was established,and theoretical calculation results indicated that the floor failure depth caused by the mining of No.2 coal seam was 9.6 meters,which was larger than the spacing between the two coal seams.On this basis,the inward offset roadway layout mode was determined,and the offset distance was calculated as 15 meters.The synergistic mechanism of bolts and cables was analyzed,and a targeted support scheme was proposed according to the geological and production conditions of the material transportation roadway.Field observation results verified that stable surrounding rock state and small deformation were achieved in the roadway after the implementation of the scheme.The research results can be referenced for the support design of mining roadways under similar geological and mining conditions.