188 / 2024-03-12 11:17:46

Exploring deformation and fracture processes of overlying strata in deep large mining height working faces based on DEM numerical method

overlying strata; deep working face; large mining height; 3DEC; deformation and breakage

Abstract: Coal seam mining in large mining height has become an important operation mode of deep and thick coal seam mining. The migration and stress distribution of overlying strata become more complex and changeable under the multi-factor coupling of high ground stress and giant turning space. In this work, based on the 3 Dimension Distinct Element Code (3DEC) numerical simulation software, a numerical model of overlying rock migration in 12110 deep mining face of Pingdingshan mining area is established, and the effects of buried depth and mining height on overlying rock movement is discussed. The results show that the large-scale numerical model can well simulate the migration of overburden rock and the distribution and evolution of overburden rock structure during mining, and the calculated results of the height of the "three zones" are basically consistent with the actual observation, and the formation and evolution process of the shear fracture zone in the actual engineering is restored. In the mining process of deep mining face with large mining height, the immediate roof has stronger periodicity than the main roof, because the breaking of the main roof is largely affected by the substructure, and the large falling space of large mining height gives more structural configuration to the substructure. With the increase of the buried depth, the initial caving step of the upper stratum decreases to a certain extent, but the influence on the height of the caving zone is not significant. The increase of mining height increases the distance between the peak position of supporting stress and the coal wall, which leads to the deterioration of surrounding rock.