Research On Law Of Underground Pressure In Steep Inclined Coal Seam Fully Mechanized Caving Under Permafrost

The Jang Cang Niangmute mininge area with a permaforst thickness of about 40 m.Because the permafrost's special characteristics of physical and mechanical properties, so that the law of underground pressure in course of mining under the permafrost is obviously different from that in the general mining environment.In particular, the sudden breaking of the permafrost may cause severe mining pressure appearing in the working face and seriously affect the safety production.Therefore,the study of the law of underground pressure in the steep inclined coal seam under the permafrost has great significance.This paper takes the two mining area of Jang Cang Niangmute mine as the research object,used theoretical analysis, physical similarity simulation and numerical simulation, reasearch the law of underground pressure in steep inclined seam under the permafrost and the breaking law of overlying permafrost.Through theoretical analysis and physical similarity simulation experiment,research the characteristics of overlying strata in steep inclined seam and the law of the deformation of permafrost;Analysis the energy size of the impact of underground on the bottom of the permaforst,used the numerical simulation method analyzed the stress distribution characteristics of the underground and the deformation and failure characteristics of permafrost.The research shows that overburden rock failure in the steep inclined seam mining has obvious zoning and asymmetry.The permafrost with coal mining deformation and separation with lower strata,the maximum separation volume 1.7m;When the mining area reaches a certain degree, the permafrost will break down and integral settlement,the maximum horizontal displacement of permafrost is 0.23 m,the vertical displacement is 4.82m;Through the calculation of the initial permafrost breaking step and periodic breaking step are respectively 335 m and 98 m. The research results have important significance for the safe and efficient coal seam mining under the permafrost layer.