The key to the layout of the roof horizontal long drilling hole is to accurately locate the range of gas-conducting fracture zone. In this paper, the discrete element method (DEM) is firstly adopted to quantitatively simulate the porosity distribution in goaf from a microscopic perspective, with the 6306 working face of the Tangkou coal mine as an engineering example. Then, the three-dimensional porosity distribution data is extracted and converted into a two-dimensional array form, which was verified by the mathematical model established by previous work. After that, combining the DEM data and mathematical model result, user-defined function (UDF) codes are written and imported into computational fluid dynamics (CFD) software to simulate the gas distribution in the goaf before and after the drilling of the working face. The results show that the gas in goaf is mainly distributed in the upper position after drilling, and the proportion of gas in the bottom position is largely reduced. The boreholes arrangement in the gas-guiding fissure zone is reasonable effectively reducing the gas concentration in goaf.

顶板水平长钻孔布置的关键是准确定位导气裂缝带范围。本文以塘口煤矿6306工作面为例，首次采用离散元法(DEM)从微观角度定量模拟采空区孔隙度分布。然后，提取三维孔隙度分布数据并转换为二维数组形式，并通过前人工作建立的数学模型进行验证。之后，结合DEM数据和数学模型结果，编写用户自定义函数（UDF）代码并导入计算流体动力学（CFD）软件，模拟工作面钻进前后采空区中的气体分布。结果表明，钻井后采空区中的气体主要分布在上部位置，底部位置的气体比例大大降低。导气裂隙带钻孔布置合理，有效降低采空区瓦斯浓度。