Research On Mechanism Of Coal And Gas Outburst Based On SIR

The coal seams in Panjiang mining area of Liupanshui（ie.LPS）Coalfield are obviously controlled by geological structures.The permeability of the top and bottom of the coal seams is very low,which is conducive to gas conservation.Most of the coal seams in Panjiang mining area are coal and gas outburst（ie.CGO）coal seams.The coal seams have high gas content,high pressure,low permeability,and dense faults.They are the worst areas of CGO accidents,and are representative in Southwest China.In this dissertation,the methods of field investigation,numerical simulation and mathematical analysis were used to establish the mathematical model of coal and gas outburst hole（CGOH）parameters and the CGO model,the equation of CGO was derived.At the same time,analyze the coal seam permeabilityβ.The critical condition for coal and gas outburst was also presented.These conclusions will be useful for gas accidents prevention.（1）Mathematical software were used to analyze the parameters of CGOH and establish the parameter equation of CGOH,which can also be applied to coal and gas outburst,extrusion and dumping;On the basis of parameter equation of CGOH,coupling gas pressure,the equation of CGO with two independent variables was derived;Coupling effective stress,gas pressure and temperature,the equation of CGO with four independent variables was derived and permeabilityβwith three independent variables.At the same time,the judgment condition 1 of P_{effective stress},P_{gas pressure}and T_temperaturefor CGO were derived.（2）Based on the principle of SIR infectious disease dynamics,the CGO and non-CGO models were constructed,the existence and stability of the equilibrium point of the outburst model were studied,the Equation ofβand the threshold R₀of permeabilityβwere calculated.For non-CGO models,the area（volume）ratio of each area with examples were analyzed.（3）The Equation ofβwith three independent variables was coupled into multi physical fields such as gas diffusion field of coal matrix,gas seepage field of coal seam,deformation field of coal seam and temperature field of coal seam to find the change rule of permeabilityβunder the conditions of Darcy flow and non-Darcy flow.At the same time,the equation of permeabilityβwith three independent variables and the threshold R₀ofβwere solved jointly,and judgment condition 1 of P_{effective stress},P_{gas pressure}and T_temperaturefor CGO were derived.Combining permeability judgment condition 1 and2,the determination conditions of permeability which controlling CGO were found.（4）The storehouse model of CGOH was established.The periodic change rule of particle kinetic energy E_Kon the storehouse circulation was finded.The existence of its critical value of kinetic energy was analyzed.The critical condition of energy for controlling CGO was proposed.The CGO is classified by taking the outburst size as the index to distinguish the energy of CGO.There are 76 figures,57 Tables and 153 references.