| With the increasing depth of coal seam mining,gas abnormal emission disaster occurs more frequently in goaf,and shows the trend of symbiotic disaster with coal spontaneous combustion.The co-occurrence disaster of gas and coal spontaneous combustion in goaf involves many aspects such as the fracture field of the overlying rock mass and the flow of multi-component gas.In this paper,based on the research background of the goaf of W1510 fully mechanized mining face in Gaohe Coal Mine,and the research on the flow field and the distribution of gas concentration in the goaf under the condition of partial Y-type ventilation and gas extraction is carried out by field measurement,theoretical analysis,similar simulation experiment and numerical simulation.Based on the research results,the regional distribution of combustion and explosion symbiosis disaster in goaf is determined,which provides the basis for the prevention and control of mine coupling disaster.By arranging the monitoring points in goaf and using beam tube to monitor the change of gas concentration in each monitoring point of goaf with different propulsive distance of working face,based on the distribution law of flow field and gas concentration in goaf on the spot.This paper puts forward the method of “two entry and one return” partial Y-type ventilation for W1510 working face,combined with the method of gas drainage from goaf in high roadway of coal seam roof to control the problem of gas concentration exceeding limit in the upper corner and goaf of the working face.Using the similar experiment and numerical simulation of the physical model of goaf,the distribution law of flow field and gas concentration in the goaf of partial Y-type ventilation is studied and compared with the measured results on the spot.It is concluded that the similar experiment and numerical simulation have certain reliability.At the same time,the spatial distribution characteristics of flow field and gas and oxygen concentration in goaf of “partial Y + high gas drainage roadway” type ventilation are compared and analyzed.It is revealed that the ventilation capacity of “partial Y + high gas drainage roadway” type is stronger than that of biased partial Y-type ventilation mode.It can better solve the problem of gas concentration exceeding limit in the upper corner and goaf of Gaohe working face.Analyzed the forming conditions,judging principles and methods of the dangerous area of the explosion symbiotic disaster in the goaf,the results of gas and oxygen concentration distribution obtained by using the similar experiments and numerical simulation are applied to determine the dangerous area of the combustible and explosive symbiotic disaster in the different height planes goaf under the condition of partial Y-type ventilation and gas extraction.It is concluded that the dangerous area of the combustible and explosive symbiotic disaster in the goaf bottom is located in the oxidation heating zone near the inlet air side of the goaf,and the area of the dangerous area is larger than the middle of the working face at the side of the inlet air,and presents a forward state along the goaf.Compared with the danger area of mine explosion symbiosis disaster in the goaf of partial Y-type ventilation,the area of danger area of “partial Y + high gas drainage roadway” type ventilation is larger,and the position of danger area beginning to appear is delayed and far away from the working face.Based on the field measurement and the comprehensive application of theoretical analysis,similarity experiment and numerical simulation,this paper fully demonstrates the importance of “partial Y + high gas drainage roadway” ventilation in the treatment of upper corner and goaf gas,and determines the dangerous area of combustible and explosive symbiotic disasters in goaf,providing the basis for the high gas easy spontaneous combustion mine goaf area burning explosion symbiosis disaster prevention. |
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