地铁盾构施工常需从既有建筑基础下穿越,如何确保上部建筑安全是施工中的难题。本文针对杭州地铁1号线双线盾构隧道下穿涌金立交桥的影响问题,采用FLAC3D有限差分软件对其进行了模拟和分析。首先,建立FLAC3D地层结构模型,再模拟双线盾构隧道推进过程中引起的涌金立交AC(西)匝道桥、主线桥、环道桥桩基沉降,最后,建立Midas civil荷载-结构模型,在最不利差异沉降工况条件下,对上部桥梁结构的附加内力及变形进行验算。验算结果表明,本工程各项指标均满足规范要求,结构强度及刚度安全储备较高。分析结果对工程提出了相关建议,为以后相关工程的设计与施工提供参考。 Subway shield construction often needs from the existing building through the foundation, how to ensure the safety of the upper part of the construction of the problem. In this paper, according to the influence of double shield tunnel on Yongjin Overpass in Hangzhou Metro Line 1, the FLAC3D finite difference software is used to simulate and analyze the effect. First of all, FLAC3D stratum structure model is established, then simulating the settlement of the AC (west) ramp bridge, main line bridge and ring road bridge during the double shield tunnel propulsion process. Finally, the Midas civil load-structure model is established, Under the most unfavorable differential settlement conditions, additional internal forces and deformation of the upper bridge structure are checked. The checking results show that all the indexes of the project meet the requirements of the code, and the structural strength and rigidity safety reserve are high. The results of the analysis put forward some suggestions for the project and provide references for the design and construction of related projects in the future.