中文摘要：

随着越来越多的地铁建成并投入运营,既有地下隧道受邻近基坑施工的影响及控制成为越来越重要的问题。通过建立考虑土体小应变的有限元模型,针对4种典型围护结构变形模式引起的坑外不同位置处隧道变形特点以及位移影响范围进行分析,结果表明：在围护结构最大变形相同而变形模式不同的情况下,坑外既有隧道的变形也会存在较大的差异。根据隧道拱顶拱底的竖向变形特点,可将基坑外不同位置的隧道根据其变形分为沉降区、变形过渡区及隆起区。悬臂型模式对坑外隧道的位移影响范围最小,内凸型与复合型模式影响范围基本相同,分布大于悬臂型,而踢脚型模式下范围最大。在实际工程中除控制围护结构最大变形值外,尚应根据周围环境特点合理控制围护结构变形模式,并尽可能避免出现踢脚模式变形。

英文摘要：

As more and more subways have been constructed and put into operation, control of the influences of the adjacent excavation on the existing tunnels becomes more and more important. Both the deformation characteristics of the existing tunnels at different locations and the influenced range of displacement caused by four deformation modes of retaining structures are analyzed through FEM modeling. The results show that under the situations of different deformation modes of retaining structures with the same maximal horizontal displacement, the deformations of the existing tunnels outside the excavations can be considerably different. According to the vertical deformation characteristics of the vault and invert of the tunnel, the soil layer outside the excavation can be divided into three zones, i.e., settlement zone, transition zone and heave zone. The effect zone on the deformation of the existing tunnel caused by the cantilever deformation of retaining structures is the smallest; for the convex and composite deformation modes, the ranges are similar and their distribution is larger than that of the cantilever deformation mode; the influenced range caused by the kick-in deformation mode is the largest among these four modes. In practice, besides controlling the maximum horizontal displacements of the retaining structures, the deformation mode of the retaining structures should also be optimized according to the surrounding environment, and the kick-in deformation of the retaining structures should be avoided.