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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。
Aiming at the influence of shallow buried large diameter shield tunnel construction in existing soft soil strata on the existing parallel tunnel with near distance, taking the Shanghai Renmin Road cross-river tunnel project as the background, the three-dimensional finite difference numerical analysis method is used to analyze the tunnel construction Deformation and soil pressure on the hole around the law of change. The numerical simulation results show that the new tunnel construction will cause the existing tunnel to be subjected to lateral compression, resulting in large compressive deformation in the arch and waist of existing tunnels and large tensile deformation in the vault and inverted arch sections. In the process of new tunneling, the earth pressure around the existing tunnel experiences three states of increase, decrease and stabilization. Comparing the numerical results with the field data, it shows that the calculated values and the measured values are basically the same. In addition, the numerical calculation is also effective to make up for the shortcomings of on-site measured displacement distribution and soil plastic zone formation. The calculation results show that both the displacement of surrounding strata and the plastic zone have increased under the influence of new tunnel construction. The results can provide reference for the design and construction of shallow buried large-diameter shield tunnels.