Study On Gas Migration Law And Prevention Technology In Narrow Coal Pillar Face Of Inclined Coal Seam

Mine gas disaster is the main disaster in the process of coal mining.With the comprehensive mechanization and centralization of the coal mining degree,the advancing speed of the coal mining face is increasing,which accelerates the formation of the large-area goaf and creates a favorable environment for the gas accumulation in the goaf.Under the mode of fully mechanized caving mining with narrow coal pillar in inclined coal seam,the narrow coal pillar is more easily deformed and damaged due to partial load pressure,and the deformed and damaged narrow coal pillar can easily pass through two adjacent working faces,resulting in more and more serious gas disaster in the working face being mined,which seriously restricts the production safety of coal mine.This paper takes(4-5)06 working face of Liuhuanggou coal mine as the research background,under the inclined coal seam narrow coal pillar fully mechanized caving mining mode,the influencing factors of gas migration in goaf are analyzed under the mode of fully mechanized caving mining with narrow coal pillar in inclined coal seam.The gas migration law in goaf of narrow coal pillar in inclined coal seam is studied by theory and simulation.Then,according to the law of gas migration,the specific gas control technology is put forward,and finally applied to field engineering practice.The main research contents and achievements are as follows:Through the FLAC3D numerical simulation software,the stability changes of narrow coal pillars during the mining process of inclined coal seam were simulated,and the plastic failure,stress and displacement generated within the narrow coal pillars were obtained.According to its distribution characteristics,narrow coal pillars are divided into three parts:complete coal pillars,fractured coal nillars and collansed coal pillars.Finally combined with the parosity of the porosity of other areas of the goaf,the porosity of each area of the narrow coal pillar is obtained,which provides a basis for the gas source of the coal mining face.By using FLUENT,the gas concentration distribution in the goaf without gas prevention and control measures and in the case of nitrogen injection in the adjacent goaf is simulated respectively,and the gas migration law in the narrow coal pillar face of inclined coal seam in the process of mining is obtained.The gas concentration distribution law of narrow coal pillar working face is obtained through the simulation of using high-level drilling field and buried pipe in return air corner in goaf.The results show that the gas concentration in the working face and upper corner can be reduced by using high-level drilling field and buried pipe to control gas.The specific technical measures of gas drainage in the goaf are put forward.Combined with other gas prevention and control measures,finally,through field measurement,summed up the prevention and control effect of gas in the mining process of narrow coal pillar working face in inclined coal seam.Finally,the problem of gas accumulation in working face and return air corner has been effectively treated,which has high application and promotion value.