盾构隧道下穿铁路群的路基加固及沉降分析

以福州地铁二号线(上洋站—鼓山站区间)为依托工程,盾构隧道下穿段要求施工对铁路两轨造成的沉降差异应控制在5 mm以内,因此有必要通过建立三维有限元模型对盾构隧道下穿引起的铁路路基沉降进行数值分析。通过MIDAS/GTS有限元软件建立数值模型对下穿工况进行模拟,研究总结了铁路轨道走向以及隧道掘进方向地表沉降的规律。数值模拟结果表明,在对地铁下穿段范围内的土体采取注浆加固措施后,盾构隧道施工对既有铁路路基造成的不均匀沉降可以得到有效的控制;同时,计算得到的管片注浆参数及盾构机内土舱压力为相似盾构隧道下穿工程的设计、施工提供了重要的参考依据。

Analysis of Sub-grade Reinforcement and Settlement of Metro Shield Tunnel Crossing Underneath Railway

Fuzhou subway line2 (Shangyang Station to Gushan Station) was taken as a foundation engineering project.As railways are just above the tunnel and the differential settlement of the steel rails caused by subway construction should be within 5 mm,therefore it's necessary to develop a 3D numerical simulation that analyze the embankment settlement induced by shield tunnel under railway track groups.The regularity of the railway embankment and the ground surface settlements along the rail axis were analyzed via finite element software MIDAS/GTS.The simulation results indicate that the grouting reinforcement to the stratum between the railway and the tunnel is an effective way to control the settlement of ground;and the values of several parameters gained in the calculation can provide valuable information for similar projects.