Study on the “three zones” of overburden fracture in the 15106 coal face of Sijiazhuang coal mine

In order to study the dynamic development law of overlying strata fissures during the mining process of 15106 working face in Sijiazhuang coal mine, based on the geological conditions of the overlying strata of the working face, theoretical development, numerical simulation and similar model experiments are used to study the development of overburden fractures zones.According to the mining control theory, the height of caving zone is 14.37-17.25 m, and the height of fractured zone is 54.8-72.6 m.Based on the UDEC software, the simulation results show that the k₂ limestone floor is 18 m from the roof of the coal seam, and the height of the k₄ limestone floor is 66 m from the roof of the coal seam.According to the similar model experiment, the height of caving zone is 18 m, and the height of fractured zone is 64 m.Theoretical development, numerical simulation and model experiments show that the height of “three zones” of the overburden is basically the same.Based on the height of the hard limestone, the height of caving zone is 18 m, and the height of fractured zone is 66 m.The results provide some theoretical guidance for the selection of high drainage lanes.