Characteristics Analysis of Roof Overburden Fracture in Thick Coal Seam in Deep Mining and Engineering Application of Super High Water Material in Backfill Mining

With the development of deep mining, the mining pressure on the working face is increasing, the failure height of thick seam roof is increasing, and the failure characteristics of roof are becoming more complex. The cracks in the overlying strata of the roof are greatly increased and activated by mining influence, which increases the impervious threat of the roof. In order to solve this problem, the failure stress model of thick coal seam roof was established; the 1308 working face of Yancheng Coal Mine was taken as the engineering background, and the FLAC3D numerical simulation software was used to simulate the formation failure process of 1308 working face with the threat of water permeability; the drilling section water injection test method was used to measure 1308 working face; High water material is used as raw material to fill 1308 working face. The results show that: (1) the failure height of overlying strata is calculated more accurately by mechanical model, and the failure characteristics are analyzed; (2) the failure height of overlying strata calculated by numerical simulation is smaller than that calculated by theory; (3) the problem of serious roof caving in thick coal seam can be effectively alleviated by filling with super-high water material.