Study On Mining Roadway Arrangement And Support Technology In Ultra-close Multiple-seams Mining

Theoretical analysis and numerical simulation and engineering verification are applied to solve this significant problem for mining roadway arrangement and support technology in ultra-close multiple-seams mining. Calculation method of floor injury failure depth is studied and verified by numerical simulation. Critical width of stable pillar has been defined by theoretical analysis and numerical simulation.Distribution of stress in pillar floor when one or two sides mined is comparatively analyzed. What’s more, distribution of stress in pillar floor of different coal pillar width is deeply studied. Based on the law of distribution of stress analyzed, arrangement principle of mining roadway in lower coal seam is determined. Determining method of rational position of roadway under goaf and pillar is given.Unstable mechanism due to deformation of the roadway under goaf and pillar is analyzed. This paper puts forward three large innovation technology: three high” bolting technology and truss support technology and full length anchoring technique.The main conclusions drawn from the analysis are as follows.(1)Mining stope stress calculation model is established, floor injury failure depth is calculated by elastic plastic theory and slip line theory. The max floor injury failure depth when 8# coalseam is mined is 32 m. Effect on floor damage depth by mining height and buried depth is analyzed by numerical simulation.(2)Based on the engineering geological condition of Duerping coal mine, this paper analyzed stability of pillar. critical width of stable pillar is between 15.5m and 19 m, so section coal pillar of 68301 and 68302 working face is stable pillar which is verified by numerical simulation. At last, critical width of stable pillar in Duerping coal mine is 15 m.(3)Distribution of stress in pillar floor when one or two sides mined is comparatively analyzed by numerical simulation. What’s more, distribution of stress in pillar floor of different coal pillar width and mining height and buried depth and layer spacing and lithology is deeply studied. Based on the law of distribution of stress analyzed, arrangement principle of mining roadway in lower coal seam is determined. When spacing of layers is less than 1.5m, roadway is under coal pillar; When spacing of layers is not less than 1.5m, roadway is under goaf. Roadway under goaf should be under stress decreasing zone and stress uniform area, so the location of roadway is determined. Roadway under pillar should be far from stress peak area, so roadway under pillar should be arranged at the area which stress concentration degree is as low as possible. The location of roadway of different pillar width is given.(4) Based on unstable mechanism due to deformation of the roadway under goaf, truss support technology and full length anchoring technique are given to construct roof wedge whole strengthening areaBased on three of the deformation features roadway under pillar, this paper puts forwards asymmetric support design and large strengthening cycle surrounding rock control. The mine pressure regularity during driving of 69301 Zheng roadway and Fu roadway showed that the arrangement and support of roadway is reasonable.