Similar Simulation Test Of Induce Coal And Gas Outburst During The Uncovering Tectonic Soft Coal By Crosscut

Coal and gas outburst always occurs in the strongly varied geological structure region, such as fault, fold and coal seam thickness and so on, forming the development of tectonic soft coal. Moreover, tectonic soft coal uncovering by cross-cut outburst is the most strong and dangerous coal and gas outburst. Therefore, the study of tectonic soft coal uncovering by cross-cut induced outburst mechanism and corresponding prevention measures have a practical significance and practical value for the safety production in coal mines. This paper studied the physical mechanic properties of tectonic soft coal, and then established the physical model of tectonic soft coal during the uncovering tectonic soft coal by cross-cut, and built up a test platform to test the outburst properties during the uncovering tectonic soft coal in the laboratory. The main research results are as follows:Regards of different coal and rock ingredients, we chose a typical sample from native structure of coal and tectonic soft coal, and made research on the physical and mechanical characteristics of the two kinds of coal, with microscope, pressure mercury, IS-100type isothermal adsorption and desorption meter, MYS-I type of test equipment on coal and rock sample seepage rate, gas coal and rock mass gas-solid coupled parameter tester. Based on the experiment, we analyzed the effect of physical and mechanical characteristics of tectonic soft coal on coal and gas outburst. The physical and mechanical characteristic of tectonic soft coal increases the danger of coal and gas outburst.Based on the research results of relationship between geological structure and coal and gas outburst, the physical model for the tectonic soft coal outburst was established. There is a reverse fault that the throw is greater than the thickness of the coal seam in the model; fole developing in the hanging wall of the fault makes the coal seam thickness changes. The basic characteristics of the physical model were summarized and mechanics analysis of the physical model was done. The outburst occurs in tectonic soft coal seam was influenced by coupling effect of physical mechanical properties, gas pressure and tectonic stress.Based on ideas of the similar material simulation test and geomechanical model test and according to the lithological and mechanical parameters of11-2outburst coal seam in Huainan mining area, similar simulation test of tectonic soft coal uncovering by cross-cut was done in the laboratory. The change laws of coal and rock stress and displacement in the process of tectonic soft coal uncovering by cross-cut were studied. The gas pressure, temperature and acoustic emissionwere in the process of gas injection and outburst were studied too.The tectonic soft coal uncovering by cross-cut of numerical model was established by simulation software of COMSOL Multiphysics to study on the evolution of stress, crack development and the law of gas migration. The results showed that there was obvious tectonic stress concentration area in the geological structures vicinity; Tectonic stress and excavation stress concentration due to the tectonic soft coal further broken and deep extended large outburst; Gas pressure played an important role in the process of coal and gas outburst start and sustained development.Finally, based on the similar simulation test results and the numerical simulation analysis of tectonic soft coal uncovering by cross-cut, it obtained the reason for the outburst during the uncovering tectonic soft coal. First, ground stress makes the coal body crusher and the elastic potential of coal body increase to create the conditions for gas to tear coal body induced gas outburst; then, the destructioned coal instability and powdered coal are carried by gas pressure.