Study On Strata Movement Law And Structure Feature Aroused By Mountainous Shallow-buried Coal Seam Mining

When mountainous shallow-buried coal seam mined, the strata behavior was intense and even some hydraulic supports crushed or the tail beam and roof beam separated. Contraposing this phenomenon, this paper analyzed the overlying strata movement law and structure features aroused by mountainous shallow-buried coal seam mining with the methods of actual investigation, actual measurement, theoretical analysis and numerical simulation. It analyzed the feature of mountainous shallow-buried coal seam working face strata behavior through survey and measurement. According to the structure of coal and strata in 1306 and 1104 working faces, it researched the strata movement law, surface deformation and slope destroy feature aroused by mountainous shallow-buried coal seam mining with the method of discrete element numerical simulation. It analyzed the strata movement's impact factors and their affecting law in mountainous shallow-buried coal seam mining through groups of numerical models. The impact factors include:the corresponding surface topography, slope angle, thickness of coal seam, direction of mining and the location of open off cut. It also raised the concept of slope crack critical depth, and gave the definition of mountainous shallow-buried coal seam after considering the corresponding surface topography, coal seam depth and the structure of overlying strata etc. On the base of these study results, it analyzed the mountainous shallow-buried coal seam mining overlying strata structure feature, stress feature and its mechanism through theoretical analysis and numerical simulation. It pointed out that the overlying strata would form independent "Two-Zone" structure after coal seam mined, the stress among the rocks was weak, and can not form bearing structure by itself. It made the supports take more weight of overlying strata, so it perform roof pressure large, dynamic load obvious and strata behavior intense. These conclusions are of important significance for guiding the mountainous shallow-buried coal seam mining safely.