Abstract:
Taking 22304 face of Shigetai Mine as an example, we analyze four impact factors affecting water and sand inrush at shallow buried coal seam with thick unconsolidated fomation and thin bedrock during mining. By means of field monitoring, indoor flow-solid coupling simulation experiment, hydrodynamics techniques, we study and analyze the specific geological condition, the pressure law caused by mining, the breaking law of thin bedrock and dynamic mechanism of runoff and sediment transport, then give the critical head and computing and judging basis of safety critical head. After observing analysis and theoretical calculation, we study mine pressure law of working face, concluded that the critical width is 52.7 m, the step distance of old top pressure for the first time is 50 to 79 m, periodic weighting step ranges from 16 to 19 m. The calculated critical water power gradient is 1.251, the critical height is 13.54 m, the actual hydraulic gradient is 3.25, we can conclude that the segment have risks of water and sand inrush.