Mine Pressure Behavior of Coal Pillar in Deep Close Distance Protective Seam Mining

For the strata behaviors at mining face of Ji_16-17-23190 return air roadway in Pingdingshan Coal Group No.5 Coal Mine, we carry out field measurement and numerical analysis. Monitoring data show that there is a stress reducing area with 6 m in the central area of coal pillar in Ji_16-17-23190 return air roadway, and stress reduction is 60%, 12 m away from goaf edge. Comprehensive field monitoring and numerical analysis results, we found that the advanced influence distance of mining pressure is 80 m, lag distance of 40 m, lateral influence distance of 40 m. Coal pillar area on the edge of mined-out area 0 to 12 m is high stress concentration zone. Comprehensive analysis of the results, we found that during the arrange of the protective layer in Pingdingshan Coal Group No.5 Coal Mine Ji_16-17 of coal seam mining face, coal pillar width value of 15 m is reasonable. At the same time, high stress concentration caused by mining should be avoided during mining arrangement to avoid the roadway deformation by mining pressure.