Study On Coupled Disaster Of Combustion And Explosion In Goaf Of Coal Seam With High Gas And Easy Spontaneous Combustion

With the depth of coal seam and mining intensity increasing,the coupled disaster caused by spontaneous combustion and gas explosion is increasingly prominent.Based on the field observation,numerical simulation and theoretical analysis,studying the danger area and fatalness of coupled disaster of combustion and explosion in the 2207 fully mechanized caving goaf of the Cuijiagou coal with high gas and easy spontaneous combustion can provide the comprehensive prevention and control technology for the coal.In the goaf,the measuring points were arranged on the spot,and the oxygen and the gas concentration in the inlet and the return air was obtained through the beam tube monitoring.With the intensity of corresponding air leakage,three zones were divided.The results show oxidation zone is wider in the intake and return air lane of goaf,and in the middle of the goaf,the width is reduced from the 36m of the inlet side to 25m of the return side under the normal conditions.And there is no danger of spontaneous combustion in goaf.The FLUENT software was used to simulate the air leakage flow field,and the three zones of the goaf were divided according to double indexes.Compared with the result of the field observation,the numerical simulation has a certain reliability,and the distribution of oxidation zone and gas concentration field can be used to guide the disaster prevention and control.The influence of air supply on the distribution of three zones in goaf was analyzed.It is concluded that with the increase of air flow rate,the oxidation zone is gradually away from the working face,but its distribution is expanding.Based on the conditions of coal spontaneous combustion and gas explosion,the mechanism of the coupled disaster of combustion and explosion was discussed.And based on the determination of the coupled risk region,the temperature field was introduced to analyze the risk of the coupled region.The numerical simulation results of oxidation zone and gas concentration field were used to divide the hazardous area of the coupled disaster under different air supply,and the width and breadth of the distribution of the dangerous region were found to increase.On the basis of the coupled dangerous area of the 2207 working face,the field and experimental data of temperature variation were introduced,and the results show that the possibility of the occurrence of coupled disaster is great when the time is the fourteenth day after the end of mining,and the preventive measures should be taken in time.Based on the field measurement,the method that numerical simulation and theoretical analysis were applied to determine the danger area and fatalness of coupled disaster and the results can be applied to provide the basis treatment for coupled disaster of combustion and explosion in goaf of coal seam with high gas and easy spontaneous combustion.