Research On Failure Laws Of Floor Above Confined Aquifer In Fushan Coal Mine

Coal is the major energy of china, it is impossible to be replaced in the coming period, but the floor water inrush is always one of the main factors restricting the safe production of the coal mine. In particular, the shallow coal resources of the coal in China have almost been exhausted, the lower coal group or deep coal seam is the inevitable choice for the future, the question that floor is threated by the confined water become increasingly apparent, so the research for the coal seam floor under the influence of mining and the confined water is more meaningful.Based on the hydrogeological data of Fushan coal mine, the paper determines that the cambrian limestone confined aquifer beneath the floor is the main aquifer threating the working face; considering coal seam floor suffered ground pressure and confined water pressure, based on elasticity theory and Mohr Coulomb strength criterion, it build force calculation model of the floor, and calculates stress state of any point within the bottom floor and the the floor damage depth and range; by similar simulation experiment, it got the floor’s vertical stress distribution, vertical displacement, failure features and maximal damage depth in the different advancing distance; using the FLAC3 D software, it simulates the floor’s vertical stress, the vertical displacement and plastic zone feature, and get the maximum damage depth of floor; according to theoretical calculations, similar simulation and numerical simulation results, combined with specific geological conditions of the 21051 working face of Fushan coal mine, it takes the measures of grouting reinforcement to reinforce the floor of working face, and adopt geophysical instruments to validate the grouting effect. The research conclusion has certain reference value for the prevention and treatment of water inrush from floor under similar mine conditions.