ＴＢＭ隧道下穿市政桥梁施工变形规律研究

针对ＴＢＭ不同角度下穿既有结构，对既有结构产生的扰动问题，依托青岛地铁１号线海泊桥站到小村庄站区间ＴＢＭ隧道下穿市政桥梁工程，利用ＦＬＡＣ３Ｄ数值模拟分析软件与现场施工监测相结合的方法，建立相应的三维地质力学模型，研究双线ＴＢＭ隧道施工对既有桥梁结构的受力特征与变形规律，揭示ＴＢＭ隧道下穿市政桥梁施工变形规律。计算结果表明:ＴＢＭ下穿会导致既有桥面板向上隆起，左线隧道开挖引起的桥面板隆起值要远远大于右线开挖；当左线隧道开挖到桥梁跨中时，桥头与桥尾隆起量最大，最大值约４．６３ｍｍ；新建隧道下穿既有结构尽量采用小角度下穿，避免既有结构发生大变形。

Deformation Law of TBM Tunnel Under Municipal Bridge Construction

This paper focus on the disturbance caused by TBM penetrating the existing structure from different angles and perturbation of an existing structure. More specifically, it focus on how TBM tunne-l of metro link one between Haiboqiao Station and Xiaocunzhuang Station in Qingdao, east China’s Shandong province, exerts force and deforms the existing bridge above. FLAC3 D simulation software was adopted and the simulation results will be compared with in-situ construction data to establish a three dimensional(3 D) geomechanical model, which is then used to reveal the mechanics principle. The results are as follows: the underpass of TBM will lead to the uplift of the existing bridge deck, and the uplift of the bridge deck caused by the excavation of the left line tunnel is much larger than that of the right line excavation;when the left line tunnel is excavated to the middle of bridge span, the uplift of the bridge head and the bridge tail reaches the maximum number, 4.63 mm. The newly built tunnel should be excavated in small angles in order to avoid large deformation of the existing structure.