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采动覆岩离层注浆地表沉陷“四区”控制模型及应用

“Four Zones” control model and application for surface subsidence of bed separation grouting mining

  • 摘要: 覆岩离层注浆技术已被证实是一种能够满足矿井无损开采与固废减排的新方法。为了有效控制采动引起的地面构筑物沉降,以关键层理论为基础对离层注浆开采全过程进行稳态分析。首次提出了采动覆岩离层注浆地表沉陷“四区”控制模型,分别为常规区、过渡区、注浆区和控制区,并推导出“四区”范围的计算公式。以3501工作面控制地面焦化厂沉降为工程背景,结合相似模拟与现场实测的沉陷观测数据对提出的“四区”模型进行验证,结果表明:相似模拟离层注浆地表沉陷曲线呈不规则的“V”字形,工作面地表下沉量先快速增大,到达最大下沉点后,地表下沉量先快速减小,随后减小速率逐渐变缓,沉陷曲线表现出明显的“四区”分布,最大下沉量为1 589 mm,出现在常规区与过渡区的接触边界,过渡区与注浆区接触边界下沉量为497.94 mm,控制区内基本无下沉;基于概率积分法预测的注浆条件下采动引起的地表下沉量、水平变形、倾斜和曲率与现场实测结果相符,但明显小于未注浆条件下的预测值,确定了注浆条件下地表变形满足构筑物 Ⅰ 级损坏等级的要求;结合矿井的实际工程地质及实际观测数据,得到常规区范围为261.19 m,过渡区范围为246.09 m,注浆区范围为655.25 m,控制区范围为199.53 m。提出的“四区”控制模型为研究离层注浆开采沉陷问题提供了基础理论依据。

     

    Abstract: The grouting technology of bed separations has been proved to be a new method which can meet the requirements of non-destructive mining and solid waste reduction. To effectively control the subsidence of ground structures caused by mining, the whole process of bed separation grouting mining is analyzed in a steady state based on the key stratum theory. For the first time, a “four zones” control model for surface subsidence under grouting bed separation was proposed, which includes natural zone, transition zone, warning zone, and protection zone, and the calculation formula for the "four zones" range was derived. Based on the engineering back-ground of controlling the subsidence of the ground coking plant at the 3501 panel, the proposed “four zones” model was validated by combining physical modelling and field measurement of subsidence. The results show that the surface subsidence curve of bed separation grouting in physical modelling shows an irregular “V” shape, and the surface subsidence of the panel first increases rapidly. After reaching the maximum subsidence, the surface subsidence first decreases rapidly, and then the reduction rate gradually slows down. The subsidence curve shows a clear “four zones” distribution, with a maximum subsidence of 1589 mm, appearing at the contact boundary between the natural zone and the transition zone. The subsidence of the contact boundary between the transition zone and the warning zone is 497.94 mm, and there is basically no subsidence within the protection zone. The predicted surface subsidence, horizontal deformation, slope, and curvature caused by mining under grouting conditions based on probability integral method are consistent with the field measured results, but significantly smaller than the predicted values under non-grouting conditions. It is determined that the surface deformation under grouting conditions meets the requirements of Grade I damage level for structures. Based on the practical engineering geology and observed data of the mine, the natural area is 261.19 m, the transition area is 246.09 m, the warning area is 655.25 m, and the protection area is 199.53 m. The proposed “four zones” control model provides a fundamental theoretical basis for studying the subsidence of bed separation grouting mining.

     

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