Research On Failure Regularity And Control Technology Of Roadway Surrounding Rock In Residual Coal Pillar

For the old mining the residual coal remining2 can not only make full use of coal resources,but also an important method to improve the rate of recovery of resources.To the coal mine enterprises,residual coal remining can not only improve the economic efficiency of enterprises,but also for the old mine,prolong its service life can,effectively alleviate the mine production.At the same time,to build a harmonious society and the protection of the ecologicalenvironment,have important significance of residual coal remining.The paper based on secondary mining of Jinmei group Shenghua 3#coal seam old mining area,Shenghua old mining technical data and residual coal remining face early disclosureon the basis of thorough study,summed up the residual coal storage structure,application of theory analysis and numerical simulation on the old mining the residual coal pillar failure law of surrounding rock in tunnel and its control technology research,the main research contents and conclusions are as follows:(1)After the roadway in the residual coal pillar,the new empty lane roadway with legacy constitutes roadway,the roadway between the small pillar once failure occurs,it will form a great range of activities Overburden"Expanding the pressure arch."(2)By using numerical simulation software analysis of the current situation of Shenghua coal pillar residue,and it is concluded that when the coal pillar width is more than 11 m,coal pillar is in stable;When the coal pillar width is 11 m,coal pillar is in the stable limit state;When the coal pillar width between 7 m and 11 m,coal pillar is in plastic state;When the coal pillar width is less than 7 m,coal pillar is in the broken state.(3)Used numerical simulation software to analyze the roadway rock pillar damage in different states in the law:① Stable roadway pillar,the stress distribution in the column from the original coal "saddle" to "arch",and also significantly reduces the stress,the maximum vertical stress is reduced from the original 7.2MPa to 3.6MPa,the coal column expands destruction;Proposed anchor+anchor cable+anchor net combination support ②Roadway in plastic pillar,the stress of coal from the original column "arch" distribution becomes uniform,and also significantly reduces stress,reduced from the original 6.9MPa to 2.2MPa,the whole pillar shear failure lose their ability to support;Proposed combination support which is anchor+anchor cable+anchor net mud and water to help;③Tunneling in broken pillar in the roadway,the stress value of the coal column decreased significantly reduced from the original 5.4MPa to 1.3MPa,the whole pillar tensile failure,loss of ability to support.Proposed anchor+anchor cable+anchor networks and top ways to help grouting combined support.