Evaluation on the Pressure Bump and Outburst Compound Dynamic Disaster

Abstract

After coal mining into the deep, pressure bump and outburst coexist, which are mutual inducers and compounds that increase the mining risk and control difficulty. The hazard evaluation of compound dynamic disaster before mining can predict the dangerous area and take preventive measures to reduce casualties and property losses. This paper establishes a mechanical model of “stress surrounding rock gas support,” taking into account the stress environment of coal body, impact tendency of coal body, gas pressure, roadway structure, and support stress. Taking, for example, 22220 working face of a mine, according to the history of composite dynamic disaster in the same level coal seam, the composite dynamic disaster evaluation grade is divided. The minimum critical stress index of composite dynamic disaster is taken as the medium risk evaluation standard, while the maximum is taken as the strong risk evaluation standard. The critical stress index of each area of the working face is calculated, and the risk grade is divided. The results show that the strong dangerous area of working face is mainly located in the open cut and the distance between the track transport and the open cut is 20∼250 m, and the medium dangerous area is mainly located in the air return roadway 40∼250 m. Compared with the comprehensive index method, the critical stress index method can predict the relationship between support strength, gas concentration after drainage, and composite dynamic disaster. Moreover, the evaluation results tend to be quantitative and conservative.