Experimental Study On The Laminar Spallation Of Coal Body And Pulverized Coal Migration During Coal And Gas Outburst

Coal and gas outburst is an extremely serious power disaster accident in the coal mine.It is very easy to cause casualties and property losses.Researchers at home and abroad have conducted a lot of research on this,but still can not fully explain the coal body evolution and protrusion mechanism in the process of coal and gas outburst,this paper independently designed and built a coal and gas outburst experimental platform that simulates different gas pressure,moisture content,stress and other coal-like conditions,and carried out coal and gas outburst simulation experiments under different gas pressures and different moisture content.The evolutionary characteristics of coal in the protrusion process in the protrusion cavity and the distribution form of pulverized coal in the roadway were analyzed,and the following research results were obtained:(1)Independently designed the coal and gas outburst simulation experimental platform,which have transparent simulated roadway.It enables visualization of the whole process of outburst.The experimental system can carry out coal and gas protrusion under different ground stress,gas pressure and coal body conditions,and can dynamically monitor the development of coal body morphology in the protruding cavity during the experiment,and continuously collect and monitor the coal seam pressure and the impact pressure of the gas in the roadway.(2)The effects of different initial conditions on coal and gas outburst were studied.During the outburst process,the coal body near the protrusion first moves,and then the coal body undergoes lamination.After the outburst start,the transport speed of the coal body shows a process of first accelerating and then slowly decelerating,and the transport speed of the particles in the coal body is up to 6m/s.The failure process of the coal body is tensile destruction,the failure time of the coal body is very short,the duration of outburst increases with the increase of gas pressure and the duration of outburst decreases with the increase of coal body moisture content.When the gas pressure is small(0.3MPa,0.4MPa)and the moisture content is high(6%),the degree of fragmentation of the coal body is small,and the fracture of the coal body shows a trend of first increasing and then decreasing,and the coal body still maintains the state of lamination after the end of the prominence.When the gas pressure is large(0.5MPa)and the moisture content of the coal body is small(2%,4%),the coal body is more completely broken,and after the lamination is greater than a certain width,the coal body far from the protrusion begins to collapse and break,and then the cavity is thrown out,forming a cavity at the tail of the cavity.(3)After the outburst is started,the coal body is broken into the roadway space,the gas pressure and the moisture content of the coal body have a greater impact on the strength of the coal and gas outburst,and the strength of coal and gas outburst increases with the increase of the gas pressure,and decreases with the increase of the moisture content;compared with the moisture content of the coal body,the gas pressure has a greater impact on the outburst strength.The distribution of pulverized coal in the protruding back roadway presents a normal distribution form,that is,the mass of pulverized coal near the protrusion and the end of the roadway is small,and the mass of the central part is the largest;the pressure of the protruding gas and the moisture content of the coal body have an impact on the protruding distance of the pulverized coal,the greater the gas pressure,the farther the protruding distance of the pulverized coal,the more dispersed the distribution of pulverized coal;the greater the moisture content of the coal body,the smaller the protruding distance of the pulverized coal,and the more concentrated the distribution of pulverized coal.Figure [51] Table [19] Reference [97]...