随着土地资源利用趋于饱和，在既有隧道上开挖超深基坑和修筑超高层建筑群已成为中心城市发展的一种趋势，确保既有隧道的安全运营是项目开发建设的前提条件。以渝中城大型城市综合体项目及下穿公路隧道为研究背景，采用Midas/GTS有限元软件建立三维模型模拟隧道施工、深基坑开挖 及建筑群加载的全过程，在分析过程中结合隧道施工特点及隧道现状检测结果，考虑围岩松动圈、隧道材料劣化等不利因素，对裂缝及局部衬砌厚度偏薄等质量瑕疵进行分析。从位移场、应力场、塑性区分布及衬砌内力变化等多方面分析项目施工给隧道带来的影响程度，得出以下结论： 1)在施工过程中，拱顶竖向位移的变化较拱侧水平位移明显； 2)基坑开挖工况对隧道位移的影响较建筑物加载工况大； 3)隧道衬砌内力变化不明显，隧道衬砌安全系数能满足规范要求，项目实施能保证隧道安全运营。

As the land resources become more and more valuable, the excavation of superdeep foundation pits and the construction of superhighrise buildings above existing tunnels have become a trend of the development of downtown area. However, ensuring the safe operation of the existing tunnels is a prerequisite for the development of the new projects. With Yuzhong Midtown Project and the existing highway tunnel running below the project as the research background, the authors establish the threedimensional model to simulate the whole process of tunnel construction, deep foundation pit excavation and building group loading by using Midas/GTS finite element software. In the process of analysis, the authors analyze the quality defects of the tunnel, such as the cracks and the lack of lining thickness at local positions, considering the features of the tunnel construction, the inspection results of the status of the tunnel, as well as the surrounding rock loosening ring and the material degradation. The authors also analyze the degree of the impact of the project construction on the tunnel in aspects of displacement field, stress field, plastic zone distribution and lining internal force changes. Conclusions drawn are as follows: 1) In the process of the construction of the project, the change of the vertical displacement of the crown is more obvious than that of the horizontal displacement of the arch side; 2) The influence of the excavation of the foundation pit on the displacement of the tunnel is severer than that of the loading of the buildings; 3) The change of the internal force of the tunnel lining is not obvious, the safety factor of the tunnel lining can meet the requirements of relevant codes and the safe operation of the tunnel can be ensured.