矿采场底板突水危害性分析

definition of water-inrush-factor is presented, and the criterion about the instability of seepage flow of water in stratified rock mass is describes by water-inrush-factor. Based on the column of rock mass in A Coal Mine, the distributions of stress in mining floors are simulated by using the numerical testing machine (RFPA) at the moment when longwall mining is pushed on to 25 meters and 50 meters respectively; and the water-inrush-factors are calculated on the basis of the relationship between permeability parameters and strain. It shows that the permeability raises, the non-Darcy flow β factor and acceleration coefficient decrease as the failure of the mining floors, and the water-inrush-factor raises subsequently. As the longwall mining is pushed on, the destroyed district extends, and the strain and water-inrush-factor increase correspondingly. For the mining floor in A Coal Mine, the water-inrush-factors are 95.1% and 619% when the working face is pushed on to 25 and 50 meters respectively.