小煤柱厚煤层开采裂隙-瓦斯场耦合及分布演化模拟

    Evolutionary simulation of coupling and distribution of mining fracture-gas field of small coal pillar and thick coal seam

    • 摘要: 矿井瓦斯是煤矿重大危险因素,为了提高安全生产水平,本研究以羊场湾煤矿为工程背景,采用多软件耦合方法揭示开采裂隙场与瓦斯场的动态耦合机制,利用UDEC软件模拟煤层开采过程中覆岩破断、位移及裂隙发育规律,量化“走向三区”和“垂向三带”的孔隙率分布。根据裂隙结果,利用ICEM CFD构建采空区物理模型,并通过FLUENT软件模拟不同开采阶段采空区瓦斯运移的规律。研究结果表明:①厚煤层在开采后,采空区瓦斯呈扇形分布或弧形分布,进风巷侧浓度低,回风巷侧浓度高,远离煤壁区域瓦斯浓度高可达0.75e2%VOL以上;②随着开采范围的扩大,裂隙发育高度增加,瓦斯在采空区上方自由升浮扩散,使得瓦斯区域扩大,呈“Z”形分布;③相邻工作面间隔6 m小煤柱开采时,煤柱两侧瓦斯易积聚形成高浓度区,区域呈“山脊”形分布。本研究通过厚煤层开采过程中裂隙场与瓦斯场的动态耦合关系,为工作面瓦斯精确治理和安全生产提供了理论依据。

       

      Abstract: Mine gas represents a major hazard in coal mining. To enhance safety performance, this study investigates the dynamic coupling mechanism between mining fracture and gas fields at Yangchangwan Coal Mine, employing a multi-software coupling methodology. UDEC simulations are used to model overburden fracturing, displacement, and fracture propagation patterns during coal seam extraction, quantifying porosity distribution within the “strike three-zones” and “vertical three-zones”. Based on fracture results, ICEM CFD constructs physical models of the goaf, with FLUENT simulating gas migration patterns at different mining stages. Key findings include: ①following thick-seam mining, goaf gas exhibits fan-shaped or arc-shaped distribution, with lower concentrations near the intake airway and higher levels near the return airway. Areas distant from the coal face reach concentrations exceeding 0.75e2%VOL. ②As mining advances, fracture development height increases, enabling free buoyant diffusion of gas above the goaf. This expands gas-affected zones, forming a “Z”-shaped distribution pattern. ③During extraction with 6 m inter-panel coal pillars, gas readily accumulates on both sides of pillars, creating high-concentration “ridge-shaped” zones. This research elucidates the dynamic coupling relationship between fracture fields and gas fields during thick-seam mining, providing a theoretical basis for targeted gas control and safe production practices.

       

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