摘要
针对软土地层中浅埋大直径盾构隧道施工对既有近距离平行隧道的影响,以上海人民路越江隧道工程为背景,采用三维有限差分数值分析方法对南线隧道施工引起北线隧道的变形和洞周土压力的变化规律进行了研究。数值模拟结果表明新建隧道施工会使既有隧道侧向受压,引起既有隧道拱腰部位产生较大的压缩变形,拱顶及仰拱部位产生较大的张拉变形。新建隧道掘进过程中,既有隧道周围土压力经历增加、减小和趋于稳定三个状态。将数值计算结果与现场实测资料进行对比分析,表明计算值与实测值基本一致。此外,数值计算还有效弥补了现场实测在土体位移分布和土体塑性区形成方面的不足,计算结果表明受新建隧道施工影响,既有隧道周围地层位移和塑性区范围都有增加。研究结果可以为浅埋大直径近距离越江盾构隧道的设计和施工提供参考。
In order to study the influence of shallow-covered and large diameter shield tunnel construction on the existing parallel tunnel in soft ground, with the Renmin road river-crossing tunnel in Shanghai as background, a 3D finite difference numerical analysis is adopted to the research on the influence of south fine shield tunnel construction on the built north line. The deformations of existing tunnel and soil pressure around it resuhed from the new parallel tunnel construction are investigated. The results show that the existing tunnel was under lateral extrusion during the parallel tunnel excavation, and great compression deformation occurred at the spring line and tensile deformation ap- peared at the crown and invert of the existing tunnel. The soil pressure around the existing tunnel experienced a se- quence of increasing, decreasing and stabilizing states during the parallel tunneling. These results of the numerical a- nalysis are qualitatively fit well with in-situ measurements. Furthermore, the numerical simulation compensates draw- backs of in-situ monitoring in distribution of ground movements and developments of soil plastic zone during new tun- nel construction. It shows that there was growth of vertical settlement of subsurface ground and plastic zone around ex- isting tunnel during new parallel tunnel excavation. Such findings can serve as references for the design and construc- tion of river-crossing shield tunnel characterized by shallow-covering, large diameter and close spacing.
出处
《地下空间与工程学报》
CSCD
北大核心
2012年第5期1065-1069,1074,共6页
Chinese Journal of Underground Space and Engineering
基金
住房和城乡建设部科技资助项目(2011-K3-28)
关键词
盾构法
平行隧道
现场监测
数值分析
shield-driven method
parallel tunnel
in-situ monitoring
numerical analysis
