THE KEY STRATUM METHOD OF RISK EVALUATION FOR WATER INRUSH IN COAL MINE

The stratum with the largest bearing capacity between coal seam and aquifer is regarded as the key stratum in preventing from water inrush,and it is simplified into a thin plate. Its fracturing span is determined by the plate theory, and is used to appraise the risk of water inrush from floor. The analyses of real examples show that the method is the simple and efficacious.