| In order to further study the mechanism of coal and gas outburst,many experts and scholars have conducted many useful explorations.However,because of its complexity,the existing technical means cannot completely eliminate the occurrence of coal and gas outburst accidents.In order to further study the coal and gas outburst mechanism,this paper focuses on three key problems of coal and gas outburst physical simulation test equipment,coal and gas outburst dynamic evolution process and coal-gas two-phase flow migration effect after outburst.The problem lied at the core,relying on the State Key Laboratory of Coal Mine Disaster Dynamics and Control(Chongqing University)to develop a physical simulation test system for coal and gas outburst.Based on the system,a physical simulation test method for coal and gas outbursts was proposed.The physical simulation tests of coal and gas outburst were carried out under conditions of mining disturbance,different stress conditions,different water cuts,and different gas pressures.The characteristics of gas field,temperature field,stress field and acoustic emission signal in coal and gas outburst were discussed in the process of dynamic evolution of coal and gas outburst,as well as the transport and disaster characteristics of coal-gas two-phase flow in coal mine roadway network system.Through systematic research,the following conclusions are obtained.(1)Independently developed a coal and gas outburst dynamic disaster simulation physical simulation test system consisting of a multi-field coupled large-scale coalmine dynamic disaster simulation test system and a mine tunnel network system.Based on the system,a physical simulation test method for dynamic disaster caused by coal and gas outburst was proposed.(2)Based on the physical simulation test of coal and gas outburst dynamic evolution process,the spatio-temporal evolution characteristics of various physical fields were discussed,and the impact force and gas pressure during coal and gas outburst pulsation development were analyzed,as well as the variation of acoustic emission signals.Simultaneously,the settling characteristics of outburst pulverized coal in free space were clarified.(3)A physical simulation test was conducted for the migration characteristics of coal-gas two-phase flow in coal mine roadway network during coal and gas outburst events,and parameters such as impact force,gas concentration and temperature during the migration of coal-gas two-phase flow in the roadway network were obtained,as well as the image information of the internal flow of the two-phase flow in the mine tunnel.Additionally,the distribution characteristics of the prominent coal fines in the mine roadway network were analyzed.(4)The physical simulation tests of coal and gas outburst in different stress state,different gas pressure and different water content had been carried out.The dynamic evolution process of coal and gas outburst under various conditions was compared and analyzed in order to highlight the change of coal state in the process.(5)Based on the comprehensive hypothesis,the Bayesian Network of coal and gas outburst was built by the obtained test data to analyzed the sensitivity of various influencing factors in the coal and gas outburst process. |
PDF Full Text Request