The Xinfu Square Station of the Fifth rail transit of Chongqing traverses across the bridge pier of Mount Huangshan interchange.The excavation of the station has great influence on the pile foundation of the existing bridge.With the help of the large-scale finite element software MIDAS GTS 2.6, we have simulated the two kinds of risk control measures.Simulation results show that the settlement of arch is 2.00 cm, which is reduced by about 20%, and the horizontal convergence is 2.82 cm, which is reduced by about 30%.At the same time, the field monitoring results show that after the tunnel excavation, the deformation indexes of the tunnel and the adjacent bridge piles are within the controllable range.All these results show that the design scheme presented in this paper is safe and feasible, and it can be used as a reference for similar projects.%重庆轨道交通五号线幸福广场站超大断面暗挖侧穿黄山立交桩基,车站开挖施工对既有桥梁桩基影响较大.借助大型有限元软件MIDAS GTS 2.6模拟了有无针对性风险控制措施两种工况,结果表明:超大断面隧道开挖采用针对性的风险控制措施后拱顶沉降为2.00 cm,减小约20%;水平收敛为2.82 cm,减小约30%.同时现场监测结果表明,采取一定控制措施进行隧道开挖后,隧道及临近桥梁桩基各项变形指标均在可控范围内.
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