Study on the Influence of Crack Anti-friction Mechanism of Coal Containing Gas on the Process of Disaster-Causing Fracture

A variety of coal pressure phenomena and coal fracture phenomena are relevant to the coal microcrack evolution, and the gas contained in coal seam makes the crack propagation more complex, therefore the disaster-causing fracture mechanism of coal containing gas urgently needs indepth study. It is found in previous studies, that coal, as a complex structure, when fractures, is not only influenced by its complex structure and mechanical properties of the coal matrix structure, but also influenced by the friction on the crack and the gas molecular force. In this study, it is further believed that in the process of crack propagation, crack tip constantly breaks into new interfaces with high surface energy, and on the new interfaces Van der Waals forces of gas molecules forms the gas adsorption film, which can reduce friction coefficient. The resistance to brittle fracture of coal decreases as the friction coefficient reduces, which makes the crack propagation farther develop and accelerates the fracture process of coal containing gas. According to the results, the gas can reduce the macro-mechanical properties of coal and rock mass, which is consistent with previous study, therefore specialized research on the physical and mechanical parameters of gas-containing coal and its disaster-causing mechanism is in urgent need, thus practical production can be accurately guided and evaluated through these researches.