Simulation experiment system of coal and gas dynamic disaster in deep mine and its application in accident analysis

The exploitation of deep coal resources is increasingly becoming a key demand of the coal industry. Howev- er,the occurrence of coal and gas dynamic disasters in deep environments such as high ground stress,high gas pres- sure,and high temperature is more complicated. The large-scale physical simulation analysis of this scientific problem is currently the most suitable research method. Therefore,based on the three core influencing factors of high ground stress,high gas pressure and high temperature,the theoretical requirements of the over-kilometer deep mining environ- ment on the indexing requirements of the outburst simulation system loading capacity,system stiffness,gas pressure and temperature were analyzed,and its critical indicators were proposed. Furthermore,the simulation experiment system of coal and gas dynamic disaster in ultra-thousand deep mine with loading sub-system and sealing sub-system as the main body was designed. The system has a vertical loading ca-pacity of ≥25 MPa,horizontal loading capacity of ≥16 MPa, system stiffness of 30 GN / m,gas pressure 6 MPa,and ground temperature control 60 ℃ ,which can meet the storage environment simulation requirements of a coal seam of 1 000-1 500 m in a deep mine with its similar ratio of 0. 6-1.0. It was applied to simulate the occurrence of the 4·19 dynamic disaster accident in Dingji coal mine,Huainan. The following conclusions were obtained that during the outburst process,the coal body stress-pressure coupling evolu- tion law at different positions behind the outburst hole was different. It can be roughly divided into four areas:the area where the outburst hole is located,the front outburst affected area,the back outburst affected area,and the unaffected area. After the initial outburst hole was formed,the velocity of gas desorption and seepage in the outburst affected area would affect the further development. The duration of stress-dominated outburst was shorter and coal amount was less. A total of 15. 86 kg of coal samples were thrown out in the experiment. It represented 34. 8 t of outburst coal at the site through conversion. The classification of the outburst coal samples is not significant,showing typical extrusion charac- teristics. The simulation results are consistent with the actual situation,which proves the applicability and functionality of the system.