Study on dynamic response characteristics of mining stress in shallow deep mining roadway

A case study was performed at the auxiliary haulage roadway of 15216 working face in Hongliulin Coal Mine to investigate the dynamic response characteristics of mining dynamic stress of hard and thick roof with shallow buried depth.The mining dynamic stress response characteristics of the working face before and after the mining were studied,and the critical coal pillar width was calculated based on the field data and the theoretical analysis.The results show that the influence range of the advance mining in 15216 working face was 275 m,and the stress of bolt and cable in auxiliary haulage roadway was relatively strongly influenced by the retreating mining,while that in the lag working face stage increased significantly but its variation range decreased distinctly.Influenced by the lateral hanging roof structure of the coal pillar,the maximum stress of the bolt at the coal pillar side was 167 kN,and the support strength of the coal pillar needed to be further strengthened.In the whole period of mining dynamic stressevolution,the stress distribution of the coal pillar presented an asymmetric ″bimodal″ characteristic.The peak stress of the coal pillar was in the range of 9 to 13 m,and the peak stress was 15.7 MPa.The coal has not yet entered the plastic yield stage,indicating that there was still a stable elastic bearing area inside the pillar.According to the principle that the static load concentration of the coal pillar was equal to its strength,its critical width was calculated to be 13 m and a reasonable roadway surrounding rock support technology was proposed.The research provides a certain reference for the roadway support and the coal pillar width retention.