中文摘要：

以某新建盾构隧道拟近距离垂直下穿苏州地铁1号线区间隧道为研究对象,采用有限元分析软件ANSYS对盾构隧道施工过程进行三维弹塑性数值模拟,分析不同间距时新建隧道垂直下穿对既有地铁隧道的影响。结果表明：应力、弯矩、轴力和土层位移均随着开挖步的增加而增加;新建隧道开挖对既有隧道的影响在3倍新建隧道直径范围之内;在条件允许的情况下,新建隧道垂直下穿既有隧道的间距应大于0.8倍新建隧道直径,否则,应采用改变施工参数、加固既有隧道周围土体等施工措施,降低既有隧道截面的应力、弯矩、轴力和土层位移的增加值,确保既有隧道结构的安全和新建隧道的顺利掘进。

英文摘要：

The article takes a new shield tunnel as research object,which crossing vertically under the tunnel of the subway Line 1 at short range in Suzhou.ANSYS software was used to make a 3D numerical simulation of the elastoplasticity in the process of shield tunneling.The influence on the existing subway tunnel crossed vertically by the new tunnel with different spacing was analyzed.The results show that the stress,bending moment,axial force and soil layer displacement all increase with excavation step.The influence of new tunnel excavation on the existing tunnel is in the range of three times diameter of the new-built tunnel.If the conditions are allowable,the spacing for the new-built tunnel crossing vertically the existing tunnel should be greater than 0.8 times of the new-built tunnel diameter.Otherwise,such measures should be taken as changing the construction parameters,consolidating the soil mass around the existing tunnel and so on to reduce the added values of stress,bending moment,axial force and soil layer displacement of existing tunnel section,to ensure the safety of the existing tunnel and the smooth excavation of new tunnel.