基坑施工对近邻既有铁路线的影响研究

Study on the Influence of Foundation Pit Construction on Adjacent Existing Railway Lines

针对和融地块基坑工程施工,运用有限元软件Plaxis 3D对施工过程进行模拟,分析开挖过程对近邻天津地下直径线、京津城际铁路及津山线的影响。结果表明:对于土体位移,地表沉降随着基坑开挖深度的增大而逐渐增大,当开挖至坑底时达到最大,坑外土体变形随着与地连墙距离的增加而逐步增大,达到最大值之后,随距离的增加呈减小趋势;对于既有铁路线结构,变形主要由基坑方向水平位移与竖向位移控制,二者均随着基坑开挖深度的增加呈增大趋势,在靠近侧基坑开挖阶段,位移增幅最大;当基坑开挖至坑底时,既有铁路线结构位移达到最大,且均小于控制值,满足规范要求。

Based on the foundation pit construction of Herong block, the finite element software Plaxis 3D is used to simulate the construction process. The influence of the excavation process on the adjacent underground diameter line of Tianjin, Beijing—Tianjin intercity railway and Jinshan line is analyzed. The results show that the soil displacement and surface settlement increase gradually with the increase of the excavation depth, and reach the maximum when the excavation reaches the bottom of the pit. The soil deformation outside the pit increases gradually with the increase of the distance from the diaphragm retaining walls, and then decreases with the increase of the distance when reaching the maximum value. For the existing railway line structure, the deformation is mainly controlled by the horizontal displacement in the direction of the foundation pit and vertical displacement, both of which tend to increase with the increase of the foundation pit excavation depth. The displacement increase is the largest in the near side excavation stage. When the foundation pit is excavated to the bottom of the pit, the displacement of the existing railway line structure reaches the maximum, and both are less than the control value, which satisfy the code requirements.