Study On Width Reservation And Stability Of Coal Pillar In 421-2 Face Of Chenjiashan Coal Mine

With the increase in mining depth in coal mining areas,the yield of coal are more and more numerous,so acceptable number is decreasing.So simplify the breadth of section coal pillar can add the recovery rate,the coal recovery rate can be improved and the service life of the mine can be extended.However,a small width of the section pillar can leave the tunnel surrounding rock in a plastic and broken area,and a large deformation of the tunnel surrounding rock can affect the safety and stability of the mining tunnel.Hence,how to achieve safe and efficient coal mining while minimising the waste of coal resources is one of the challenges faced by the mine.Based on the engineering and geological condition of Chenjiashan,study the suitable section coal pillar,the support parameters of the roadway and the stability of the roadway by using comprehensive means such as theoretical analysis,numerical simulation and field monitoring.The major research results are as follows:(1)The mechanical structure model of composite roof under the condition of coal pillar retaining roadway is adopted,the bearing characteristics of section coal pillar are studied,the distribution law of vertical stress of confined coal pillar is revealed,and the influencing factors of vertical stress of coal pillar are analyzed.(2)Established a numerical calculation model for multiple working conditions,study stability of section coal pillar in roadway excava and face mining is stydied,and the variation characteristics of stress field,displacement field and plastic zone of roadway surrounding rock in the breadth of coal pillar is 5m,6m,7m,8m,9m and10 m respectively,decided the suitable size of small coal pillar as 8m.(3)According to the analysis of the section coal pillar and the roadway stability,use the theoretical formula and simulation method,determine the support parameters of the bolt(cable)of coal pillar roadway in 421-2 working face。(4)Through the on-site monitoring of surrounding rock deformation of transportation roadway in 421-2 working face,the optimized coal pillar width is evaluated and demonstrated.The optimized coal pillar width can meet the requirements of mine safety production.The determination of the reasonable size of coal pillar in 421-2 working face of Chenjiashan coal mine is of milestone significance to alleviate the tension of mining connection,improve the resource recovery rate and prolong the service life of the mine.This paper features 52 images,18 tables and 120 references.