Coal rupture evolution law of coal and gas outburst process

Abstract：The article developed a set of coal and gas outburst simulation equipments by ourselves. Keal-hme observation of the coal and gas outburst process was obtained by using a high-speed video camera, and the coal rupture evolution law of coal and gas outburst process were analyzed. The author analyzed 12 tests and the results show that coal and gas outburst is a mechanical process of development. It has gone through a birth, start, development and stop four stages. Because of the effects of gas pressure and the radial stress of holes in the wall, coal and gas outburst experiences mutiple intermittent development; during the experimental conditions, coal and gas outburst starts, it consumes less than 0.1 s from the development to the end ; coal in different parts of the test apparatus has different trajectory during the moment of outburst. After outburst, the author analyzed the crack distribution of the coal, and found that cracks emerged almost parallely, the crack angle was between 65°and 70°. The crack was like approximate arc, and the center position was in a prominent mouth. The test of experiment also shows that there is a critical value between 0. 481 MPa and 0. 764 MPa gas pressure. It can highlight the succession,which makes a big outburst possible.