The 4th International Symposium on Mine Safety Science and Engineering (ISMSSE2018)

236 / 2018-05-05 15:02:40

Research on the Destabilization Mechanism and Patterns of Rock Mass when Coal and Gas Outburst Initiates

Coal and gas outburst, outburst initiation, destabilization mechanism, stress trajectories

Gas of Coal Mine & Coal and Gas Outburst > Coal and gas outburst

The initiation of coal and gas outburst is the catastrophe point of rock mass from quasi-static to sudden outburst. It’s a destabilization phenomenon, and its occurrence conditions determine whether the outburst can happen. Based on nonlinear dynamics, some general mathematical conditions are presented. The varying pattern of stress field topological structure in coal wall before outburst initiation is mapped and characterized by principal stress trajectories. It shows that the whole rock mass system is likely to occur bifurcation instability when outburst initiates. In addition, the existing researches on the properties of coal with high stress and high gas pressure indicate that the rock mass system may also occur extreme point instability. Both instability patterns will occur in most of outburst initiation cases. According to actual mining conditions, 4 typical destabilization patterns of coal wall when outburst initiates is summarized and characterized, they are extrusion, rib spallation, collapse under pressure, and break off. All the destabilization patterns may lead to further continuous outburst development.