Study on water inrush prediction and floor failure factors analysis in pressurized coal mining

In order to effectively prevent and control floor water inrush accident occurred by the mining operation, a plastic theory and empirical formula were appli ed to analyze and summarize the factors affected to the floor failure and the deposition factor and the mining design factors were divided. Based on No. 15 seam in sha ngkong coal mine as a study background, an aquiclude thickness, water pressure of the seam floor, seam thickness and inclined length of the coal mining face were sel ected as the main control factors, a"deposition-mining” multi factor combined model was established and a FLAC3 Dsoftware was applied to simulate the floor vertical st ress and plastic zone distribution law under the combination of different factors. The results showed that the depth of the mining failure zone would be very sensitive to the width variation of the coal mining face, the aquiclude thickness and the water pressure of the seam floor would play a control role to the scope of the confined water pressurized zone and the aquiclude thickness would have higher influences. A fluctuation of the mining thickness would have a weak influence to the floor failure. An id ea of the equivalent failure depth was firstly provided and would be applied to the water inrush coefficient method. The water inrush danger of the pressurized mining in No.15 seam was predicted. The proposals were make to reduce the width of the coal mining face and to enhance the water detection and discharging at the coal minin g wall, the front location of the coal mining face and other mining boundary in order to prevent and control the water inrush.