地下通道开挖引起临近地铁隧道回弹位移分析

Analysis on Rebound Displacement of Adjacent Metro Tunnels by the Excavation for the Underpass

临近地铁隧道建造地下通道,需预先评价地下通道开挖对地铁运营安全的影响。结合地下通道工程,针对通道B段垂直正交近距上跨地铁区间隧道等条件,采用Boussinesq解和Mindlin解计算通道开挖卸载产生的附加应力,分层总和法计算地铁隧道产生的回弹位移。结果表明,Boussinesq解和Mindlin解两者计算结果相差不大,Boussinesq解更偏于安全;Boussinesq解和Mindlin解两者计算的地铁隧道底部(轨底)回弹位移均小于1 mm,地铁隧道顶部最大回弹位移分别为6.2 mm、5.3 mm,均满足城市轨道交通线路轨道竖向变形、相对变形曲率、隧道结构绝对沉降量等要求,为地下通道施工的超前控制提供了依据。

Before the construction of the underpass adjacent metro tunnels, some influences for the underpass excavation construction on the subway operation safety will be evaluated. Base on the underpass project, the construction conditions of vertical, orthogonal, near distance and crossing-over metro tunnel for the underpass channel B are considered, and the additional stress caused by the underpass excavation is calculated by the Boussinesq and Mindlin solution method, and the rebound displacement of subway tunnel is calculated by the layer-wise summation method. The results are shown as follows： the results for the Boussinesq and Mindlin solution method has little difference, and the results for the Boussinesq solution method is more secure. The rebound displacement at the bottom of subway tunnel is both less than 1 mm by the Boussinesq and Mindlin solution method, and the maximum rebound displacement at the top of subway tunnel is respectively 6.2 mm, 5.3 mm. Which meet the requirements of urban rail transit safe operation, including the vertical deformation of track, the relative deformation curvature, absolute settlement of subway structure, and the basis for advanced control of underpass construction is provided.