盾构下穿既有铁路路基变形分析研究

Analysis of Deformation Analysis of Shield Underpassing Existing Railway Subgrade

摘要: 地铁隧道盾构掘进过程会不可避免地造成地层扰动，致使隧道影响区域地层结构应力状态改变及位移变形，进一步影响既有铁路线路的安全及稳定性。在某地铁隧道掘进工程中，盾构掘进依次下穿既有铁路上行线、下行线和牵出线，影响风险较高。为避免既有铁路产生过大位移变形，本文基于Midas GTS有限元软件，通过建立三维全过程模型，对施工方案进行充分安全评估。结果表明，铁路路基最大沉降为0.785 mm，垂直铁路方向最大水平变形值为0.198 mm，沿铁路方向的最大水平位移值0.358 mm，均满足控制标准，表明本次工程具有良好的安全性。

Abstract: The shield tunneling process of subway tunnels will inevitably cause formation disturbances, resulting in changes in the stress state and displacement deformation of the stratum structure in the tunnel affected area, which further affects the safety and stability of the existing railway lines. In a subway tunneling project, the shield tunneling passes through the existing railway up-line, down-line and lead-out line in turn, and the impact risk is high. In order to avoid excessive displacement deformation of existing railways, this paper establishes a three-dimensional whole-process model based on Midas GTS finite element software to fully evaluate the safety of the construction scheme. The results show that the maximum settlement of the railway subgrade is 0.785 mm, the maximum horizontal deformation value in the vertical railway direction is 0.198 mm, and the maximum horizontal displacement value along the railway direction is 0.358 mm, all of which meet the control standards, indicating that the project has good safety.