Mechanical Analysis of Dynamic Disturbances and Static Stress with Different Mining Methods

To study the mechanism of rock burst accidents with different mining methods, the overburden structural characteristics were studied in detail during the long-wall face mining period, and elastic foundation beam theory (EFBT) was used to analyze the dynamic disturbance and static stress when mining with different methods. The results show that the gangue cannot effectively support the fractured main roof, and the range of caved overburden is so large that it needs to be supported by the coal seam. A mining method with a tall mining height leads to a maximum stress concentration coefficient in an advanced coal wall, and a mining method for a thin coal seam or the top-slice mining method leads to the formation of a minimum stress concentration coefficient in an advanced coal wall. The structural characteristic of near-field key strata mainly depends on the caving height of the gob, and the deflection and the weighting interval of the main roof are different for different mining methods. The different mining methods have a large influence on the dynamic disturbance induced by the main roof, and this large influence is caused by the structural characteristics of both far-field strata and near-field key strata. The mining depth, the proportion coefficient, the tensile strength and the thickness of the main roof have a large influence on the deflection and released energy of the beam or composite beam, but the elastic modulus of the main roof and the blank space height of the voussoir beam structure have little influence on the deflection and released energy of the beam or composite beam. The research results aim to provide a theoretical basis for the prevention and control of rock bursts when using different mining methods.