| Gas accident is the first and foremost one of coal mining accidents nowadays, while the effective way to solve gas accident is conducting gas drainage. Through consulting mass data, so as to analyse and settle gas drainage situation at home and abroad, especially relating and analyzing the gas drainage situation of China particularly. Via studying the literatures of gas drainage in China, discovering that there are many problems existing in gas drainage. And relating and analyzing relevant problems detailedly. Thereby ensuring the research meaning and purpose of this thesis and also ascertaining research technique route. Through studying porous medium theory, discussing the characters of porous medium, and also studying the flowed equation of gas in porous medium: law of conservation of mass, the flow law of anisotropism medium, etc. In vertical three zones theory in goaf, introducing the definition and partition of three zones. And studying the permeability of overlying rock, discussing gas discharge characteristics in goaf. About the influencing major factor of gas discharge in goaf:these two aspects (natural occurrence factors and mining conditions factors) are to be discussed. Then, studying the gas seepage law in goaf, and via the predictive methods of gas emission quantity, so as to deduce the measurement theory of gas emission quantity, thereby conducting indirect calculation. Summarizing frequently-used drainage methods in goaf:roadway drainage, gas drainage from boreholes, buried (put) tube drainage, and their respective advantages and disadvantages. Through analyzing the practice data of DongQu coal mine and the physical truth of drainage face, choosing the appropriate drainage method:using buried tube drainage and auxiliary gas drainage from boreholes. And devising drainage parameters. Via gas drainage in goaf, solving the problem of transfinite gas in the upper corner of14411working face on DongQu coal mine effectively,thereby ensuring safety in production of working face. |
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