Investigation and Numerical Simulation Study on Mining Effect of Double Protective Seam

LUO Jianjun

doi:10.3969/j.issn.1008-4495.2015.06.003

Abstract：To aim at the problem of the protection range division of the overlying protected seam affected by the mining of the underlying double protective seam in Wulan Coal Mine, calculation was carried out on the change process of the deformation field of the overlying No. 2 and 3 outburst seams after the mining of the underlying No. 7 and 8 seams based on the finite difference method, according to the physical and mechanical parameters and the geological characteristics of roof and floor rock strata of the protective seam and by using FLAC3D simulation software, the roof-to-floor convergence of the protected seam after the mining of the protective seam was obtained, the maximum expansion deformation of the coal seam was calculated and it was greater than the critical point of 3 ‰ thickness of coal seam, and the protection range of the protected seam along the dip and strike after the mining of the protective seam was determined. The results showed the pressure relief angles of the overlying No. 2 and 3 protected seams along their upper and lower boundaries of the dip after the mining of No. 7 and 8 double protective seams were respectively 78° or 57° and 80° or 77°, and that along the their strike were 52° and 61°. The research results have significant theoretical guidance role for the mining effect investigation of the protective seam and the safe mining of overlying No. 2 and 3 outburst seams in the future in Wulan mine.