招贤煤矿近距离煤层下行开采采动影响分析与可行性研究OA

To study the mining influence and feasibility of downward mining in the No.2 coal seam of the Fourth Mining Area in Zhaoxian Coal Mine,the No.3 coal seam working faces(4301-4304)and the No.2 coal seam working faces(4201-4202)were selected as research subjects.A combined approach of theoretical analysis and numerical simulation was employed to analyze the overlying strata structure evolution and interlayer rock failure characteristics during close-distance coal seam downward mining.The results indicate that the floor failure depth induced by No.2 coal seam mining is 9.86 m,significantly less than the average interlayer spacing of 31.09 m between the two seams.Analysis based on slip line and elastoplastic theories confirms that mining the upper No.2 coal seam does not damage the No.3 coal seam,allowing downward mining under proper support and safety measures.Given the small spacing between the No.2 and No.3 coal seams in the Fourth Mining Area,which classifies them as close-distance seams,the residual coal pillars from the No.2 coal seam induce stress concentration in the No.3 coal seam working face.During No.3 coal seam mining,the roof experiences elevated stress due to the combined influence of overlying pillar stress and its own advance abutment pressure.Therefore,during subsequent mining of the No.3 coal seam,attention must be paid to hazard control,including water inrush and residual coal spontaneous combustion.