地铁隧道穿越地裂缝施工对既有桥梁影响分析

以西安地铁二号线穿越长安立交和f6地裂缝段为例，利用ABAQUS有限元软件对地铁穿越地裂缝施工对既有桥梁建立三维模型进行模拟分析，并将现场监测数据与数值模拟结果进行对比分析，得出以下结论：1）地铁穿越地裂缝施工对既有桥梁桥墩具有一定的影响，对第3排桥墩沉降影响明显；2）地裂缝在短期内对地铁隧道开挖的影响不明显，需对地裂缝处结构进行长期监测。同时，建立了地铁隧道与地裂缝相距不同水平距离的二维模型，通过分析给出了在西安地区临近地裂缝开挖地铁隧道的建议最小设防距离为3倍隧道直径。

Analysis on Influence on Existing Bridge Imposed by Construction of Metro Tunnel Crossing Ground Fissure

3D model is established and analysis is made on the influence on the existing bridge imposed by the construction of a subway tunnel crossing a ground fissure,and the site monitoring data and the simulation results are analyzed,with a section of Xi＇an Metro line 2 crossing Chang＇an overpass and f6 ground fissure as an example.The conclusions drawn are as follows： 1） The construction of the Metro tunnel crossing the ground fissure has some influence on the existing bridge piers,especially on the settlement of the third row of the bridge piers;2） The influence of the ground fissure on the excavation of the Metro tunnel in short term is not obvious,therefore long-term monitoring should be made for the tunnel structures near the ground fissure.Meanwhile,2D model of different distances from the Metro tunnel to the ground fissure is established,analysis is made and the minimum fortification distance to excavate Metro tunnels near ground fissures in Xi＇an area is proposed to be at least 3 times of the tunnel diameter.