“U+I”型采煤工作面瓦斯抽采与浮煤自燃耦合研究

为了研究“U+I”型工作面进风量和顶板巷抽采负压对工作面瓦斯浓度与采空区氧化带宽度的影响，协调瓦斯抽采和浮煤自燃之间的关系。以2306综放面为工程背景，基于“U”型冒落岩层孔隙率分布公式和流体通用控制方程建立采空区数值模拟解算模型。采用CFD软件对不同进风量、不同抽采负压下的工作面瓦斯浓度和采空区氧化带宽度进行模拟，结果表明:随着工作面风量的增加，工作面和顶板巷瓦斯浓度减小，但工作面处浓度减幅逐渐变小而顶板巷浓度减幅几乎不变；提高顶板巷抽采负压，对减少工作面瓦斯浓度效果明显，顶板巷自身瓦斯浓度先增加再减小，采空区进风侧氧化带宽度变窄，回风侧和采空区中部氧化带宽度增加，总体上增加了采空区浮煤自燃的危险性但影响程度有限。

Study on coupling between gas drainage and spontaneous combustion of float coal on "U+I" type coal mining working face

In order to study the influence of supply air rate and drainage negative pressure in roof roadway at "U+I" type working face on the gas concentration of working face and the width of oxidation zone in goaf, and coordinate the relationship between gas drainage and spontaneous combustion of float coal, a numerical simulation model of the goaf was established based on the void fraction distribution formula of "U" type caving rock layer and the general governing equations of fluid by taking the 2306 fully mechanized caving face as the engineering background. The gas concentrations of working face and the widths of oxidation zone in goaf under different supply air rates and drainage negative pressures were simulated by using CFD software. The results showed that with the increase of supply air rate in the working face, the gas concentration in the working face and roof roadway decreased, but the reduction amplitude of the gas concentration in the working face became smaller gradually, while that in the roof roadway was almost unchanged. Increasing the drainage negative pressures in the roof roadway presented an obvious effect on decreasing the gas concentration in the working face, and the gas concentration in the roof roadway increased first and then decreased. The width of oxidation zone in air intake side of goaf became narrower, and the width of oxidation zone in air return side and the middle of goaf increased. The risk of spontaneous combustion of float coal in goaf increased as a whole, but the degree of influence was limited.