Study On Overburden Rock Destruction Features When Mining Steeply Dipping Seam Beneath The Permafrost

Qinghai Jiangcang NiangMute mine is the first large underground coal mine establishingin high altitude alpine region in the world. The mine is located in plateau alpine region, theupper part of the bedrock is covered with thick permafrost, and the angle of coal seam is large,which make the conditions of the underground mining special. Studies suggest that the law ofpermafrost and overlying strata failure due to underground mining is one of the importantbasis to ensure mining safely and efficiently.In this paper, through similar material simulation experiments, numerical calculation andtheoretical analysis method, the overburden rock destruction features when mining steeplydipping seam beneath the permafrost in NiangMute mine is studied. The similar material andthe ratio to simulate permafrost at normal temperature is got through repeated experiments.Through physical simulation and numerical simulation, the deformation and failuremorphology of the permafrost layer and overlying strata, the extent of damage, the failureheight influenced by mining height, and so on are studied. Comprehensive analysis indicatedthat the initial destruction of permafrost in steeply dipping seam mining will show horizontalO-X breaking model, periodically breaking of permafrost will bring face pressure a certainimpact, and the destruction of overlying strata is still more obvious zonation and asymmetry.The reasonable size of coal pillar and the failure height of overlying strata at different miningheight are also analyzed.