水位变化下盾构隧道管片纵向变形特征研究

Research on Longitudinal Deformation Characteristics of Shield Tunnel Segment Under Water Level Change

水位变化幅度过大会对江底隧道结构安全造成较大影响,依托南昌轨道交通4号线过赣江段在建工程,研究过江隧道在水位变化下管片纵向变形特征。采用现场监测与数值模拟相结合的方法,首先借助表贴式混凝土应变计,测得管片内侧拱底、拱腰及拱顶处纵向应变,再利用有限元软件进行数值计算,得到隧道管片纵向应力分布情况,最后将数值模拟结果与现场监测结果进行对比分析,得到主要结论:水位变化会对盾构隧道管片纵向变形造成一定规律性影响,随着水位下降,拱底和拱顶区域受压,而拱腰区域则发生受拉现象;水位变化对管片拱顶区域应变影响最大,而对拱底区域影响最小。

If the water level changes too much, the structural safety of river tunnel will be greatly affected. Relying on the construction project of Nanchang rail transit line 4 crossing Ganjiang River, the longitudinal deformation characteristics of tunnel segments under the water level change were studied. Firstly, with the help of surface mounted concrete strain gauge, the longitudinal strains at the inner arch bottom, arch waist and arch crown of the segment were measured. Then, the finite element software was used for modeling to obtain the longitudinal stress distribution of the tunnel segment. Finally, the numerical simulation results were compared with the field monitoring data, the main conclusions are as follows:(1)the change of water level has a regular effect on the longitudinal deformation of shield tunnel segment. With the decrease of water level, the arch bottom and arch crown are compressed, while the arch waist is tensioned;(2)the change of water level has the greatest influence on the strain of segment vault region, and the least influence on the strain of segment bottom region.