摘要
综合考虑中间主应力、横观各向同性冻胀和围岩位移释放的影响,基于冻融圈整体冻胀模型建立了寒区隧道冻胀力的弹性解、塑性统一解以及塑性区半径的隐式计算方程,给出冻结围岩弹-塑性状态的判定方法,对所得结果进行可比性分析和对比验证,并探究各因素对冻胀力和塑性区半径的影响特性,借助支护施作时机量化了围岩位移释放的距离描述。研究表明:解答具有很好的可比性且被文献模型试验所验证;统一强度理论作为屈服准则可充分发挥冻结围岩的承载潜能,所得冻胀力和塑性区半径明显减小;不均匀冻胀系数和体积冻胀率对冻胀力和塑性区半径的影响显著,应考虑围岩横观各向同性冻胀特性并采取有效的防排水和保温抗冻措施;位移释放系数较小时冻胀力偏大、位移释放系数为1时塑性区半径最大,恰当的支护施作时机有利于隧道施工及运营安全。所得结果可为寒区隧道设计提供一定的理论指导。
The elastic solution and the unified plastic solution for the frost heaving force of tunnels in cold region as well as the implicit equation of plastic zone radius were proposed in this study based on the overall freeze-thaw circle frost heave model. The proposed solution can comprehensively account for the influences of the intermediate principal stress, the transverse isotropic frost heave and the displacement release of surrounding rock. Meanwhile, an approach was provided to determine the elastic-plastic state of frozen surrounding rock. Furthermore, comparability analysis and verification of the proposed solution were performed. The effects of various factors on the frost heaving force and plastic zone radius were investigated. Finally, the distance description of the surrounding rock displacement release was quantified through the supporting time. It was found that the proposed solution has good comparability and was verified by model tests in reference. As the yield criterion of frozen surrounding rock, the unified strength theory can fully make use of its bearing potentiality, the frost heaving force and plastic zone radius are decreased obviously. The frost heaving force and plastic zone radius are significantly affected by the anisotropic frost heave coefficient and the volume frost heave ratio. Therefore, it is necessary to consider the transverse isotropic frost heave of surrounding rock and take effective measures of tunnel waterproofing and drainage as well as insulation and frost resistance. The frost heaving force is large when the displacement release coefficient is small, while the plastic zone radius reaches its peak value when the displacement release coefficient reaches one.Therefore, a proper supporting time is beneficial to the safety of construction and operation for tunnels in cold region. The obtained results can provide some theoretical guidance for the design of tunnels in cold region.
作者
张常光
高本贤
李天斌
单冶鹏
ZHANG Chang-guang;GAO Ben-xian;LI Tian-bin;SHAN Ye-peng(School of Civil Engineering,Chang’an University,Xi’an,Shaanxi 710061,China;Stake Key Laboratory of Geohazard Prevetion and Geoenvironment Protection,Chengdu University of Technology,Chengdu,Sichuan 610059,China;School of Highway,Chang’an University,Xi’an,Shaanxi 710064,China;School of Civil Engineering and Architecture,Beijing Jiaotong University,Beijing 100044,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2021年第11期2967-2976,共10页
Rock and Soil Mechanics
基金
国家自然科学基金项目(No.41202191)
地质灾害防治与地质环境保护国家重点实验室开放基金项目(No.SKLGP2020K022)
长安大学中央高校基本科研业务费专项资金项目(No.300102280108)。
关键词
寒区隧道
统一强度理论
冻胀力
位移释放系数
横观各向同性冻胀
cold region tunnel
unified strength theory
frost heaving force
displacement release coefficient
transversely isotropic frost heave
