Study on disaster of water and sand inrush of weakly cementedthick conglomerate on deep mining coal seam

In view of the problem of coal mine water inrush accident, based on the theoretical study of water and sediment inrush mechanism and the analysis of water and sediment inrush cases, combined with the hydrogeological and engineering geological characteristics of Taran Gaole Coal Mine, through the physical mechanics of thick layer of conglomerate aquifer, thetest analyzed the mathematical evaluation model of the factors affecting the risk of water inrush from the height of the water-conducting fracture zone and the thickness of the aquifer. Based on the ArcGis platform and the "water-rich index method", the results of water-rich evaluation and safety zoning of roof aquifer were obtained, and the risk zoning of water inrush and sediment burst was obtained. The results show that the coarse sandstone under the condition of poor cementation, easy loosening and relatively soft failure under disturbance is subjected to the splitting effect of hydrostatic pressure on it and the hydrodynamic pressure exerted by groundwater to overcome resistance. Driven by both hydrostatic and hydrodynamic pressures, the sand grains in the aquifer break through. The sand in the aquifer passes through the congenital fracture channel such as faults and folds and the network fissure channel and the caving crack channel caused by the mining activity, and moves into the working face, the gob and the roadway as the water flow direction moves toward the gush, which leads to the water and sand collapse accidents.The interaction of the four elements of water sand source, power source, channel and flow space is the internal mechanism leading to water inrush. The water guiding fracture zone and the fault structure development zone are the key points for prevention and control of water inrush accidents.