高地应力条件下的隧道围岩松动圈分布规律研究

发布时间：2018-09-10 19:08

【摘要】：在高地应力岩体中进行隧道施工时,常发生围岩开裂、弹射、崩塌、变形过大等工程灾害,将对施工及后期运行的安全产生较大危害。通过研究高地应力条件下隧道围岩应力应变状态和围岩松动圈分布规律,可合理优化隧道设计与施工参数,有效保障该类工程高效安全的施工。本文在系统介绍常用高地应力判释标准和方法的基础上,提出了基于Hoek-Brown强度准则的高地应力状态理论判定公式。通过引入中间主应力,得到了适用于高地应力条件的修正的Hoek-Brown岩体强度准则,并根据弹塑性理论推导出硐室围岩塑性区应力、塑性区半径和松动圈半径的解析解。在宝汉高速某深埋隧道中运用所提出的高地应力判别标准得出该隧道位于高地应力区。选取典型断面ZK163+868和YK163+775,根据修正的Hoek-Brown强度准则进行弹塑性理论计算,并结合MIDAS/GTS有限元数值模拟和声波法现场实测,分析隧道围岩应力状态、塑性区和松动圈分布范围。结果显示三种方法所得松动圈范围较为接近,且分布规律基本一致,证明基于修正的Hoek-Brown强度准则可较为准确的计算出围岩松动圈半径。同时得出在高地应力场中隧道围岩松动圈半径随中间主应力的增大呈先减后增的趋势,随支护力的增大呈减小趋势,且分布并不均匀,由于构造应力的影响水平方向松动圈半径大于竖直方向。
[Abstract]:When tunnel construction is carried out in high ground stress rock mass, engineering disasters such as cracking of surrounding rock, ejection, collapse and excessive deformation often occur, which will cause great harm to the safety of construction and later operation. By studying the stress and strain state of surrounding rock and the distribution law of surrounding rock loose circle under the condition of high ground stress, the design and construction parameters of tunnel can be reasonably optimized, and the efficient and safe construction of this kind of project can be effectively guaranteed. Based on the systematic introduction of the commonly used criteria and methods for judging and releasing high in-situ stress, this paper presents a formula for determining the state of high in-situ stress based on Hoek-Brown strength criterion. By introducing the intermediate principal stress, a modified Hoek-Brown rock mass strength criterion suitable for high in-situ stress condition is obtained, and the analytical solutions of stress, plastic zone radius and loosening circle radius of surrounding rock around the chamber are derived according to the elastoplastic theory. In a deep buried tunnel of Bao-Han Expressway, it is concluded that the tunnel is located in the area of high ground stress by using the criterion of high ground stress. The typical section ZK163 868 and YK163 775 are selected to calculate the elastic-plastic theory according to the modified Hoek-Brown strength criterion. The stress state, plastic zone and loose zone distribution range of tunnel surrounding rock are analyzed by combining MIDAS/GTS finite element numerical simulation and field measurement with acoustic method. The results show that the range of loosening circle obtained by the three methods is close and the distribution law is basically the same. It is proved that the radius of the loosening ring of surrounding rock can be calculated more accurately based on the modified Hoek-Brown strength criterion. At the same time, it is concluded that the radius of loosening circle of tunnel surrounding rock decreases first and then increases with the increase of intermediate principal stress, and decreases with the increase of supporting force in high ground stress field, and the distribution is not uniform. Because of the influence of tectonic stress, the radius of loosening circle in horizontal direction is larger than that in vertical direction.
【学位授予单位】：西安工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U451.2

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