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剥蚀区影响下大巷布置优化及煤柱稳定性研究

Study on roadway layout optimization and coal pillar stability under the influence of denudation area

  • 摘要: 为研究浅埋煤层在剥蚀区影响下大巷布置优化及煤柱稳定性, 以瑶渠煤矿西采区回风大巷为研究对象, 采用理论分析、数值模拟和现场工程验证等方法, 研究了剥蚀区影响下巷道变形破坏特征与能量演化规律, 分析了在偏应力屈服准则和能量判据下不同尺寸煤柱的破坏情况, 确定了巷道布置优化后合理的煤柱尺寸。结果表明: 剥蚀区会使围岩应力增加、应变能积聚, 致使巷道围岩变形破坏加剧, 坚硬岩层受扰动时应变能变化较小, 但不会隔断能量的传递, 而较软煤岩体中会产生较大的应变能改变。巷道布置优化后, 掘进过程中煤柱内偏应力与应变能呈先递增再稳定最后递减趋势, 巷间煤柱小于9 m时, 煤柱内偏应力与能量曲线均呈“钟形”分布, 且均大于屈服破坏的极限值; 煤柱宽度为10~13 m时, 偏应力与能量曲线转变为“马鞍形”, 煤柱内部小于屈服极限区域逐渐增加, 承载能力逐步提高; 煤柱宽度大于13 m时, 回风大巷与剥蚀区距离过近, 其间煤体在剥蚀区和回风大巷双重应力和能量叠加下产生失稳破坏。最后, 综合确定煤柱合理尺寸范围为10~12 m, 考虑保持煤柱稳定性同时减小剥蚀区的影响, 采用10 m煤柱进行工程实践, 监测结果表明巷道整体变形量较小, 围岩稳定性控制较好。

     

    Abstract: For the optimization of roadway layout and coal pillar stability under the influence of denudation areas in shallow buried coal seams, the air-return roadway in the western mining area of Yaoqu Coal Mine was selected as the research object. Through a combination of theoretical analysis, numerical simulation and field engineering verification, the deformation and failure characteristics, as well as the energy evolution law of the roadway under the influence of the denudation area, were thoroughly examined. Additionally, the failure behavior of coal pillars of varying widths was analyzed based on the partial stress yield criterion and energy criterion. Ultimately, the optimal coal pillar size was determined following the optimization of the roadway layout. The results indicate that the presence of a denudation area significantly increases the stress in the surrounding rock and leads to the accumulation of strain energy, thereby exacerbating the deformation and failure of the roadway's surrounding rock. When the hard rock strata are disturbed, the change in strain energy is relatively minor. However, this disturbance does not impede the transfer of energy. In contrast, the soft coal rock mass exhibits a substantial change in strain energy. Following the optimization of the roadway layout, the deviatoric stress and strain energy within the coal pillar initially increase, then stabilize, and ultimately decrease during the excavation process. When the width of coal pillar between roadways is less than 9 m, both the deviatoric stress and energy curves within the coal pillar exhibit a "bell-shaped" distribution, with values exceeding the threshold for yield failure. When the width of coal pillar is between 10 and 13 m, the deviatoric stress and energy curves transform into a "saddle-shaped" distribution. During this period, the area within the coal pillar where the stress is below the yield limit gradually expands, and the bearing capacity correspondingly increases. Conversely, when the coal pillar width exceeds 13 m, the air-return roadway becomes too close to the denudation area. The coal body becomes unstable due to the superposition of dual stress and energy influences from both the denudation area and the air-return roadway. Accrodingly, the optimal width range for the coal pillar is determined to be 10 to 12 m. Considering both the stability of coal pillar and the minimization of the denudation area's impact, a coal pillar width of 10 m is selected for engineering implementation. Further monitoring demonstrates that the overall deformation of the roadway is minimal, and the deformation of surrounding rock is effectively controlled.

     

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