水平互层围岩隧道破坏机理及其范围预测模型
FAILURE MECHANISM AND SCOPE PREDICTION MODEL OF HORIZONTAL INTERBEDDED SURROUNDING ROCK TUNNEL
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摘要: 水平互层围岩因其显著的层理构造, 导致其破坏形式相较于均质围岩有较大区别. 目前针对水平互层围岩的研究集中在单一破坏模式, 未考虑破坏形式的多样性. 为探究水平互层围岩的破坏范围, 首先按其层理面划分为单层围岩进行分析, 将围岩破坏分为拉破坏、楔形剪切破坏和拱形剪切破坏3种典型模式, 分别建立了岩梁受拉分析模型和拱形关键块剪切分析模型进行分析, 提出了相应的破坏准则, 并引入塌落系数和临界高度对不同破坏模式的孕育条件进行研究, 将此方法应用于矿井巷道和隧道工程实例中, 与既有方法进行比较, 验证了单层围岩破坏机理模型的可靠性, 同时代入离层破坏算例中验证其实用性. 并以此为基础, 结合破坏范围层间连续条件和破坏休止条件建立水平互层围岩破坏预测模型, 将上述水平互层围岩破坏模型应用于补连塔矿巷道实例. 结果表明本文预测的水平互层围岩破坏范围与数值模拟结果、真实塌落情况吻合较好. 研究成果可为水平互层围岩隧道支护方案设计提供理论基础.Abstract: Due to the remarkable bedding structure of horizontal interbedded surrounding rock, the failure form of horizontal interbedded surrounding rock is quite different from that of homogeneous surrounding rock. The current research on horizontal interbedded surrounding rock focuses on a single failure mode, without considering the diversity of failure modes. In order to explore the failure area of horizontal interbedded surrounding rock, firstly, it is divided into single-layer surrounding rock to analysis according to its bedding plane. The horizontal interbedded surrounding rock failure is divided into three typical failure modes: tensile failure, shear failure at wedge boundary and shear failure at arch boundary. The rock beam-tension analysis model and the arch key block-shear analysis model are established respectively to analysis the failure of single-layer surrounding rock, and the corresponding failure criteria are proposed. And use the slump coefficient and critical height to study the division conditions of different failure modes. This method is applied to mine channel and tunnel engineering examples, and compared with the existing methods to verify the reliability of the failure mechanism model of single-layer surrounding rock. At the same time, it is substituted into the example of abscission damage calculation to verify the practicability of the failure mechanism model of single-layer surrounding rock. Based on this, a horizontal interbedded surrounding rock failure model is established by combining the interlayer continuous conditions and the failure rest conditions of the failure range. The above horizontal interbedded surrounding rock failure model is applied to the example of Bulianta mine roadway, and the results show that the horizontal interbedded surrounding rock failure range predicted by this method is in good agreement with the numerical simulation results and the actual collapse situation. The research achievements can provide a theoretical basis for the design of support scheme of tunnel in horizontal interbedded surrounding rock.