The excavation of large-diameter shield tunnels in soft soils inevitably impacts adjacent high-speed railway infrastructure. This study investigates the effects of constructing a 14.02 m large-diameter shield tunnel on the deformation of a nearby high-speed railway subgrade in soft soils of Shanghai, and evaluates the effectiveness of various protective measures. A numerical model was developed to simulate the horizontal deformations of railway subgrade piles, as well as the vertical and horizontal deformations of track slab resulting from shield excavation. Comprehensive real-time monitoring of track slab displacements in both vertical and horizontal directions, along with ground surface deformation, was conducted. The accuracy of the computational model and the effectiveness of the implemented protective measures were validated through field measurements. The results demonstrate that isolation piles with coupling beams proved to be the most effective method for protecting the railway subgrade. The maximum observed ground settlement above the tunnel reached −20.3 mm, while the peak heave was recorded at 3.7 mm. Notably, the additional vertical and horizontal deformations of the high-speed railway track were successfully constrained within the 2-mm threshold. These findings provide valuable insights for safety assessments and the implementation of protective measures in similar projects.

中文翻译：

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软土地体中大直径盾构隧道开挖对相邻高速铁路路基变形的影响及防护措施的有效性


在软土中开挖大直径盾构隧道不可避免地会影响相邻的高速铁路基础设施。本研究调查了在上海软土地基中建造 14.02 m 大直径盾构隧道对附近高速铁路路基变形的影响，并评价了各种防护措施的有效性。建立了一个数值模型来模拟铁路路基桩的水平变形，以及盾构开挖引起的轨道板的垂直和水平变形。对轨道板在垂直和水平方向的位移以及地表变形进行了全面的实时监测。通过现场测量验证了计算模型的准确性和实施的保护措施的有效性。结果表明，带连接梁的隔振桩被证明是保护铁路路基的最有效方法。在隧道上方观察到的最大地面沉降达到 -20.3 mm，而峰值隆起记录在 3.7 mm。值得注意的是，高速铁路轨道的额外垂直和水平变形成功地被限制在 2 mm 阈值内。这些发现为安全评估和在类似项目中实施保护措施提供了有价值的见解。