采空区孔隙率分布对采空区气体流动具有重要影响。为研究错层位采空区孔隙率对瓦斯流动规律的影响,以镇城底矿22202错层位巷道布置工作面为工程背景,通过理论研究推导错层位采空区孔隙率分布的数学模型,建立错层位采空区孔隙率分布三维空间函数,分析错层位巷道布置形式对采空区孔隙率分布的影响;运用FLUENT模拟揭示了错层位与传统巷道布置工作面及采空区浅部区域瓦斯运移变化规律;通过现场实践,进行瓦斯浓度的监测。结果表明:相较于传统工作面,错层位采空区孔隙率呈现“一高一低”不对称U形分布特征,巷道布置差异对采空区整体瓦斯分布影响较小,但对工作面及回风侧采空区浅部流场有较大影响;其次错层位工作面存在的起坡段,增加了采空区漏风风阻,减少了采空区漏风量,提高了工作面通风效率且回风巷位于煤层顶板利于瓦斯排放,可有效解决工作面上隅角瓦斯超限问题。错层位巷道布置能有效降低工作面瓦斯积聚浓度,可充分保障工作面安全高效生产。

The distribution of porosity fraction in goaf has an important influence on the fluid flow ingoaf. In order to explore the impact of porosity on the fluid flow pattern in staggered roadway layoutgoaf, the 22202 staggered roadway layout working face in Zhenchengdi Mine is taken as the engineeringbackground. In this paper, the mathematical model of porosity distribution in goaf with staggered road-way layout was deduced through theoretical analysis, the three-dimensional space function of porositydistribution in goaf with staggered roadway layout was established, and the influence of porosity in goafwith staggered roadway layout was examined. FLUENT numerical simulation was revealed the variationlaw of gas migration in staggered and traditional roadway layout working faces and shallow areas ofgoaf. Throuth the field practice, the gas concentration is monitored. The results showed that comparedwith the traditional roadway layout working face, the porosity of staggered roadway layout goaf presenteda U-shaped distribution characteristics of “ one high and one low ” , and the difference in roadway lay-out had little influence on the overall gas distribution in the goaf, but had a great influence on the shal-low flow field of the working face and the return airway side goaf. The slope section of the staggeredworking face increases the air leakage in the goaf, reduces the air volume of the air leakage in the goaf,improves the ventilation efficiency of the working face and the return air lane is located on the roof ofthe coal seam, which is conducive to gas emission and able to solve the problem of gas overrun in theupper corner of the working face effectively. The staggered roadway layout can efficiently reduce the gasaccumulation in the working face, which is beneficial to fully guarantee a safe and efficient productionof working face.