Mechanism of mining subsidence in coal mining area with thick alluvium soil in China

Based on a wealth of measured data and the special occurrence condition of coal seam in the Huainan coal mining area of China, this paper proposes a new idea, which is to first separate the overlying bedrock and quaternary alluvium upon coal seam, then study regularities of mining subsidence, respectively, and finally, make a comprehensive research. A method of combining the physical simulation, theoretical analysis, and experimental data is adopted; the internal mechanism behavior and the characteristics of the surface subsidence in coal mining areas with thick alluvium are investigated. The results show that the subsidence in thick alluvium coal mining areas consists of four parts: the subsidence of alluvium soil following the bedrock subsidence caused by coal mining; the synergy subsidence between alluvium soil and bedrock; the subsidence due to groundwater loss and consolidation of the alluvium soil in coal mining area; and the compacting subsidence of shallow soil under the disturbance of coal mining. This theory can be used to completely explain the particularity of surface subsidence in coal mining areas with thick alluvium and provide the basis for establishing the prediction model.