Early warning information evolution characteristics of water inrush from floor in underground coal mining

Early warning information evolution characteristics are of great significance to the risk reduction of water inrush from floor in underground coal mining. In this paper, stress, pore water pressure, and water inrush position are used as the early warning information indicators. A physical simulation experiment of water inrush from mining floor was carried out, which revealed evolution characteristics of the stress, pore water pressure in the whole process of the floor water inrush from birth, development to the catastrophe. Also, the position of water inrush in the experiment was observed and verified by the thin-plate theory. The experiment shows that the fluctuation of the pore water pressure after a sharp rise and the continuous increase of the vertical stress can be regarded as the early warning information of floor water inrush. The position of water inrush is located at the intersection point between the center of the inclined direction of working face and the distance from open-off cut 18 cm, which is in agreement with the result of the experiment. The research results are of great significance to the short-term risk prediction and the safe mining above the confined water.