Research On The Gas Drainage Technology Of The Bottom Drainage Roadway In High Gas Thick Coal Seam Of Yu'wu Mining

High gas thick coal seam roadway driving speed is slow,mining face gas frequency overrun,mining efficiency is low,the occurrence of gas disaster accidents can not be effectively controlled,seriously restricting the safe and efficient production of coal mine.Therefore,in this paper,with the help of numerical simulation software FLAC3D,comprehensive use of theoretical analysis,field measurement and other methods.Taking N2203 working face of Yuwu coal industry as the engineering background,the gas drainage technology of bottom drainage roadway is comprehensively and systematically studied:(1)From three aspects of coal spatial distribution,coal metamorphism and coal adsorption characteristics,this paper analyzes the attached characteristics of No.3Coal Seam in Yuwu coal industry,and concludes that the occurrence of coal seam gas is affected by geological structure,surrounding rock conditions,hydrogeology,coal seam buried depth and collapse column and other factors.This paper analyzes the current situation of gas drainage in Yuwu coal industry,and finds out the problems existing in gas drainage in Yuwu coal industry.(2)Through numerical simulation,the stress distribution and deformation failure law of surrounding rock of bottom drainage roadway in different layers are analyzed,and the reasonable layer of bottom drainage roadway in Yuwu coal industry is finally determined.The horizontal direction is arranged in the middle of two roadways,and the vertical direction is arranged at the position 10m away from the coal seam floor.The reasonable support method of bottom drainage roadway in Yuwu coal industry is given.(3)The method to determine the effective extraction radius of boreholes is given.The effective extraction radius is 2.5m and the drilling spacing is 5m.Based on the characteristics of the existing hole sealing technology,the sealing method suitable for the bottom drainage roadway of Yuwu coal industry is given.Finally,the sealing length is not less than 10m.(4)The results of industrial test in Yuwu coal industry show that the gas content is reduced to less than 6.14m~3/t after 150 days of drainage,which meets the requirements of gas drainage index,and N2203 bottom drainage roadway has achieved very good drainage effect.There are 61 figures,20 tables,and 81 references in the paper.