摘要
通过数值模拟和理论分析,研究了盾构隧道开挖面挤出破坏机理。首先,利用有限元软件进行了数值模拟,揭示了隧道开挖面挤出破坏的局部失稳模式,得到了盾构隧道开挖面挤出破坏的局部失稳比和极限支护压力。此外,还进行了摩擦角和相对埋深对局部失稳比率和极限支护压力的参数敏感性分析。其次,基于极限分析方法,提出了一种考虑局部失稳模式的隧道开挖面挤出破坏新机制。新的被动破坏机理由五个圆锥台和作用在圆锥台上的分布力组成。通过对定义的角度和隧道开挖面局部失稳直径进行数值优化,计算得到挤出破坏模型的上限解,进而研究了摩擦角和相对埋深对局部失稳比的影响。比较了数值模拟和理论分析得出的局部失稳比结果。最后,将获得的被动极限支护压力与现有方法进行了比较,表明新的挤出破坏机理为极限支护压力提供了较为满意的预测结果。
Through virtue of numerical simulation and theoretical analysis the problem of passive failure mechanism of shield tunnel is studied.Firstly,the numerical simulations with finite element software are performed to reveal the partial instability modes of passive failure of a pressurized tunnel face.The partial instability ratio and limit support pressure for passive failure of shield tunnel face are obtained.Moreover,the parameter sensitivity analysis of friction angle and the relative cover depth on partial instability ratio and limit support pressure are also discussed.Secondly,a new passive failure mechanism of tunnel face considering the partial instability modes is proposed based on limit analysis methods.The new passive failure mechanism is composed of five truncated cones and a distributed force acting on the truncated cones.The distributed force is determined using a modification of the silo theory for passive modes.The upper-bound solution for passive failure mechanism are calculated by numerically optimizing with respect to the defined angles and partial instability diameter on tunnel face.Then the effects of friction angle and the relative cover depth on the partial instability ratio are conducted.he results of partial instability ratio obtained from numerical simulation and theoretical analysis in this paper are compared.Finally,the obtained passive limit support pressures and the existing approaches are compared,which indicates that new passive failure mechanism provides relatively satisfactory results for limit support pressures.
作者
王林
韩凯航
郭彩霞
解廷伟
骆建军
Wang Lin;Han Kaihang;Guo Caixia;Xie Tingwei;Luo Jianjun(Beijing Jiaotong University,Beijing 100044,China;Shenzhen University,Shenzhen 518060,China;Beijing University of Technology,Beijing 100124,China)
出处
《土木工程学报》
EI
CSCD
北大核心
2020年第S01期50-56,共7页
China Civil Engineering Journal
基金
国家自然科学基金(51908371)
广东省重点领域研发计划(2019B111108001)
珠江三角洲水资源配置工程课题(CD88-GC02-2020-0038)
关键词
盾构隧道
开挖面稳定性
极限分析
挤出破坏机理
局部失稳
shield tunnel
face stability
limit analysis
passive failure mechanism
partial instability