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连采连充采场顶板充前变形机理及控制对策

Deformation mechanism and control measures of roof deformation before filling in continuous mining and continuous backfilling quarries

  • 摘要: 充填采场顶板在充填前的变形决定充填率上限,显著影响充填效果,为探究连采连充采场顶板的充前变形机理,通过研究采场顶板在充填前的变形演化规律,提出了4种典型分布模式,并基于弹性地基梁理论,建立了相应模式的力学模型,分析了影响顶板充前变形的关键因素,揭示了顶板充前变形机理,进而提出了针对性的控制措施。结果表明:顶板充前变形在二阶段充填时显著增加,且在所开采支巷内近似呈线性分布;根据不同开采阶段的顶板变形特征,可将充前变形分为对称分布、弧形分布和似线性分布,由此建立了4种分布模式;荷载释放率和支巷宽度对4种模式的影响均较为显著,相邻支巷充前变形在大扰动条件下将影响后续充填效果;围岩应力释放和承载结构支撑导致顶板充前变形呈对称分布,超前扰动是导致顶板充前变形呈非对称分布的主要原因;煤柱通过控制奇数巷顶板充前变形,间接降低偶数巷顶板充前变形;奇数巷充填体通过直接控顶,减小偶数巷充填期间顶板的充前变形;据此提出了提高一阶段充填体长期强度以提高结构承载、提高两阶段充填体的短期强度以缩短临空时间、施加临时支护加固顶板以抑制下沉的联合控制措施,实现了现场充填工作面顶板下沉的有效控制。该研究阐明了连采连充采场顶板充前变形机理,可为类似工程的工艺优化及覆岩变形控制研究方面提供了借鉴。

     

    Abstract: Based on the mining and filling contradiction, cemented backfilling mining technology with continuous mining and continuous backfilling methods was proposed, and the deformation of the roof before filling determines the upper limit of the filling rate, which significantly affects the filling effect. Four typical distribution patterns were proposed by studying the roof’s deformation evolution law before filling, and a corresponding mechanical model was established based on the theory of elastic foundation beam. The key factors affecting the deformation of the roof before filling were analyzed. The mechanism of the roof deformation before filling was revealed, and the targeted control measures were proposed. The results show that the deformation of the roof before filling increases significantly in the two-stage filling, and it is approximately linearly distributed in the branch alley. Accordingly, the roof deformation before filling can be classified into symmetric distribution, arc-shaped distribution, and seemingly linear distribution, and thus four distribution patterns are established. The influence of load release rate and branch width on the four patterns is significant, and the deformation before the filling of neighboring branches mainly affects each other under large disturbance conditions. The surrounding rock stress release and bearing structure support lead to the symmetric distribution of roof deformation, and the over-disturbance is the main reason for the asymmetric distribution of roof deformation. The coal pillar indirectly reduces the roof deformation of even-numbered lanes by controlling the deformation of odd-numbered lanes. The filling body of odd-numbered lanes can reduce its deformation before filling deformation during the filling period of even-numbered lanes by directly controlling the roof. The combined control measures of improving the long-term strength of the first-stage filling body and the short-term strength of the two-stage filling body to shorten the proximity time and apply temporary support to reinforce the roof to inhibit subsidence are proposed to achieve effective control of the filling face in the field. The combined control measures of increasing the long-term and short-term strengths of the first-stage filling body to shorten the proximity time and applying temporary support to reinforce the roof to inhibit subsidence were proposed to achieve adequate control of the filling face in the field. The study elucidated the deformation mechanism of the roof before filling in the continuous mining and continuous filling quarry, which can provide a reference for the optimization of the process and the control of overburden deformation in similar projects.

     

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