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倾斜厚煤层综放工作面过空巷覆岩演化特征与不同充填控制方法对比试验研究

Evolution characteristics of overlying strata in inclined thick coal seam fully-mechanized mining faces passing abandoned roadway and comparative experimental study on different backfilling control methods

  • 摘要: 倾斜厚煤层综合机械化放顶煤回采工作面过空巷由于倾角的存在相比于水平煤层的岩层运动和矿压显现更加频繁,片帮、冒顶和压架等难题更加突出。针对该难题,以南岔煤业1213-1综放工作面过空巷为工程背景,综合采用理论分析、力学计算、数值模拟和工业试验的方法,研究倾斜厚煤层综放工作面过空巷围岩破坏机理以及围岩应力和变形变化规律,并对比分析木垛支护和超高水材料充填2种方法的控制效果。结果表明:① 通过支架载荷与基本顶来压作用、工作面与空巷不同位置处基本顶弯矩2组综放工作面过空巷力学模型以及倾斜厚煤层综放工作面1213-1过空巷三维数值计算模型,揭示了围岩破坏主要影响因素为工作面和空巷间的煤柱宽度和空巷的倾角,工作面倾斜方向的不同位置随工作面回采,垂直应力变化程度变大,并且距离空巷越远,采动条件下空巷附近的垂直应力变化程度越低,而当回采综放工作面距离空巷较近时,垂直应力变化程度越剧烈,易产生应力集中现象导致围岩发生大变形;② 基于FLAC3D数值软件得出超高水材料充填空巷后,有效提高了空巷围岩整体强度,降低了空巷区域应力集中,且大幅减少了空巷顶板变形量;木垛支护空巷效果不明显,垂直应力和变形量与空巷无支护时整体差别较小;③ 工业现场试验对比可知,木垛支护方案支护效果差,巷道变形严重,且局部倾角大的区域木垛倾倒,顶板岩煤体漏顶;超高水材料充填方案可较密实地支撑顶板,增强了空巷围岩承载能力,有效控制了围岩变形,能够保障综放工作面过空巷的安全稳定性。

     

    Abstract: In inclined thick coal seam fully mechanized caving mining faces, the passage through abandoned roadways exhibits more frequent strata movement and ground pressure manifestations compared to horizontal coal seams due to inclination effects, with significantly exacerbated challenges including rib spalling, roof collapse, and pressurizing of hydraulic support. Taking the 1213-1 fully mechanized caving face in Nancha Coal Mine as an engineering case for roadway crossing operations, this research systematically combines theoretical modeling, mechanical computation, numerical simulation, and industrial experimentation to elucidate the failure mechanisms and stress-strain characteristics of surrounding rock masses in steeply dipping thick coal seams during abandoned roadway crossings, with comparative analysis of control efficiencies between wooden cribbing support scheme and super-high water material backfill scheme. The results demonstrate: ① Through establishing 2 mechanical models analyzing shield load interactions with main roof weighting effects and main roof bending moments at different face-roadway positions, combined with 3D numerical modeling of the 1213-1 face crossing operation, it was revealed that the critical factors controlling surrounding rock failure are the coal pillar width between working face and abandoned roadway along with roadway inclination. Vertical stress redistribution intensifies progressively along the face dip direction during mining advancement, showing reduced stress variation magnitude in areas farther from the abandoned roadway under mining disturbance. However, when the caving face approaches the abandoned roadway, vertical stress fluctuations become significantly amplified, inducing stress concentration phenomena that trigger substantial rock mass deformation. ② FLAC3D numerical simulations indicate that super-high water material backfill significantly enhances the composite strength of surrounding rock in abandoned roadways, effectively mitigates stress concentration within roadway zones, and substantially reduces roof deformation magnitudes. Conversely, wooden cribbing support demonstrates limited effectiveness, showing minimal differences in vertical stress distribution and deformation patterns compared to unsupported roadway conditions. ③ Field trial comparisons demonstrate that wooden cribbing support scheme yield poor support performance characterized by severe roadway deformation, with structural collapse occurring in high-inclination zones and subsequent roof material leakage. In contrast, ultra-high water material filling provides dense roof support, enhances roadway surrounding rock integrity, effectively controls deformation, and ensures safe stability during fully mechanized caving face advancement through abandoned roadways.

     

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