Study On Width Optimization Of Coal Pillar In Fully Echanized Coal Face With Large Mining Height In Xiaobaodang No.1 Well

With the development of science and technology,comprehensive mechanization of large mining height mining in thick coal seam production has been widely used.How to improve the recovery rate,reduce the waste of coal resources,and realize the high yield and high efficiency of the coal mine is the subject that the coal industry workers continue to study.This article around the section design,the reasonable coal pillar size problem,small insurance when a well as the engineering background,the mine reasonable 2-2 coal seam fully-mechanized working face coal pillar parameters optimized research,combined with numerical simulation and field measurement to determine the reasonable coal pillar size in the section of the mine,research achievements in thick coal seam mining height are broken section width of coal pillar mining research to provide certain reference and guidance.The results are as follows:(1)the strength test of surrounding rock was adopted to analyze the coal body with medium hard strength and the roof sandstone with medium strength.The strength of floor strata is high;(2)from the observation of surrounding rock structure,it is concluded that there are obvious cracks and destruction in the shallow coal and rock mass of the coal pillar,but the overall integrity is relatively good,which indicates that the coal pillar supports well and can be optimized for the size of the coal pillar.(3)through the analysis and calculation of two ideas of safety factor method and limit equilibrium theory,the range of coal pillar of protective roadway on the first mining face of xiaobaodang no.1 well is 18.68?24.17m.(4)by comparing the vertical stress distribution and plastic zone distribution characteristics of coal pillars with different widths of 15m,20m and 25m,it is concluded that the supporting effect of 25mand 20m coal pillars is good,and the limit stress value of coal pillars is close,which can provide sufficient supporting strength,and the deformation of coal pillars is within a reasonable range.Comprehensive analysis of the selection of 20m section pillar can not only achieve a good support roadway,but also improve the coal recovery rate,so priority is given to the 20m pillar.(5)through on-site monitoring and analysis,it can be concluded that:the maximum displacement in the advance range of the coal pillar side working face in the return air roadway is 88mm respectively.The support strength is lower and the deformation is larger than that of the coal pillar because of the fiberglass bolt support.The maximum relative displacement of the top and bottom plate is 95mm.If the bolt force increase is less than 20kN,the anchor cable force has enough surplus coefficient.Therefore,after the coal pillar is reduced from 25m to 20m,the roadway surface displacement is very small.Although there is an increase,the increase is very small.The surrounding rock deformation is small and tends to be stable,which indicates that the optimization result is feasible.The research results of this paper provide a theoretical basis for determining the reasonable size of coal pillar in xiaobaodang no.1 well and provide a reference for the retention of coal pillar in similar mining conditions.