深埋软岩隧洞围岩变形破坏分区规律反演分析

发布时间：2018-07-02 21:59

本文选题：深埋隧洞 + 全长锚固　；参考：《铁道工程学报》2017年03期

【摘要】：研究目的:榴桐寨隧道是新建成都至兰州铁路线的关键性控制工程,其围岩大变形问题十分突出,而目前对深埋隧洞围岩流变条件下的变形预测尚无成熟的计算方法。本文在总结现有围岩变形研究成果的基础上,将隧洞围岩简化为理想弹塑性介质并布设全长锚固锚杆,基于锚杆-围岩协调变形原理,分析杆体表面摩阻力及其轴力的分布规律,由静力平衡条件推导锚杆中性点处的最大轴力值,进而建立变形稳定后围岩的塑性区及松动区半径公式,从理论上确定榴桐寨隧道围岩的松动区及塑性区范围,为优化围岩支护方案及参数提供重要的技术支撑。研究结论:(1)工程实际中,围岩流变是导致深埋隧洞出现大变形的根本原因,隧洞围岩变形通常在初期锚杆支护一段时间后才趋于稳定;(2)隧洞围岩与锚杆协调变形,杆体所受正、负摩阻力的分界面即为杆体中性点,该点杆体与其周围岩体的相对位移及表面摩阻力为零,但其所受轴向拉力达到最大值;(3)通过锚杆所受最大轴力可对变形稳定后的隧洞围岩塑性区及松动区范围进行反演分析,围岩塑性区及松动区范围的大小随岩体黏聚力和内摩擦角的增加而减小,随隧洞半径的增加而增大,但受支护阻力的影响不大;(4)现场应用结果表明,基于锚杆轴力反分析隧洞围岩分区规律的方法是合理可行的,该研究成果对于类似隧洞工程的安全快速施工具有一定的借鉴意义。
[Abstract]:Research purpose: the Yutongzhai Tunnel is a key control project for the newly built Chengdu to Lanzhou railway line, and the problem of large deformation of surrounding rock is very prominent. However, there is no mature calculation method to predict the deformation of the surrounding rock under the condition of rheology of the deep buried tunnel at present. On the basis of summarizing the existing research results of surrounding rock deformation, the tunnel surrounding rock is simplified as an ideal elastic-plastic medium and a full-length anchoring anchor rod is arranged, which is based on the principle of coordinated deformation between anchor and surrounding rock. Based on the analysis of the surface friction and its axial force distribution, the maximum axial force at the neutral point of the anchor rod is derived from the static equilibrium condition, and then the formulas of the plastic zone and the loose zone radius of the surrounding rock after deformation and stabilization are established. The range of loose zone and plastic zone of surrounding rock of Yutongzhai tunnel is determined theoretically, which provides important technical support for optimizing the supporting scheme and parameters of surrounding rock. The conclusions are as follows: (1) in engineering practice, the rheology of surrounding rock is the fundamental cause of large deformation of deep buried tunnel, and the deformation of surrounding rock of tunnel tends to be stable only after a period of initial bolting support; (2) the deformation of tunnel surrounding rock and bolt is coordinated, and the deformation of rock mass is positive. The interface of negative friction is the neutral point of the bar body, and the relative displacement and surface friction between the rod body and the surrounding rock mass are zero. (3) the plastic zone and loose zone of the tunnel can be inversely analyzed by the maximum axial force of anchor rod. The range of plastic zone and loose zone of surrounding rock decreases with the increase of cohesive force and angle of internal friction of rock mass, increases with the increase of tunnel radius, but is not affected by the support resistance. (4) the field application results show that, It is reasonable and feasible to reverse analyze the zoning rule of surrounding rock of tunnel based on the axial force of anchor rod, and the research result has certain reference significance for the safety and fast construction of similar tunnel engineering.
【作者单位】：西安科技大学;中铁十二局集团第二工程处;
【基金】：陕西省自然科学基础研究计划项目(2014JM2-5052) 中国博士后科学基金资助项目(2015M582761XB) 国家自然科学基金资助项目(51474173)
【分类号】：U451.2

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