Analysis of prevention mechanism of upper protective seam mining on rock rockburst induced by thick conglomerate

The purpose of this paper is to analyze the prevention effects of the upper protective seam mining on the rockburst induced by thick conglomerate. The gateway of 25110 coal face is used as the research object based on the geological and mining conditions of the mining area 25 in Yuejin Coal Mine. Theoretical analysis is used to study the mechanism of the rockburst induced by the dynamic-static loads and the theoretical basis of the prevention effects provided by the upper protective seam mining. Numerical simulation is performed to determine the change of displacement, velocity, stress and plastic distribution of the roadway floor under the same strength of dynamic disturbed stress; and simulation experiment is also conducted to study the response rules of acceleration and dynamic stress of the floor with artificial seismic source under the circumstances that when the upper protective seam was mined or not. The results show that the upper protective seam mining can effectively release the high stress inside the surrounding rocks and the soft and loose rock strata is formed after the roof rock strata of gob naturally caving, which can efficiently attenuate the dynamic disturbed stress wave and reduce the occurrence of rockburst. Therefore, the prevention effects are achieved to a certain extent when the upper protective seam mining is applied under thick conglomerate. Under the thick conglomerate rockburst prevention has certain guiding significance.