大直径盾构隧道穿越高速铁路桥梁关键技术

Key Technologies of Large Diameter Shield Tunnel Undercrossing High Speed Railway Bridge

以苏州桐泾路北延工程大直径盾构隧道穿越沪宁高速铁路(上海—南京)桥梁桩基为工程背景,对隔离桩+MJS(Metro Jet System)注浆加固综合地层处置措施进行了数值模拟,并对穿越过程的施工控制措施进行了实践检验。结果表明:综合地层处置措施能有效控制桥梁墩台的变形,可降低至不采取措施时的6%~10%,并满足不超过2 mm控制值;结合控制盾构掘进参数、同步注入克泥效等施工主动控制措施,盾构左线、右线穿越期间桥梁墩台变形稳定,其各方向实测最大位移均未超过0.5 mm。隔离桩+MJS注浆加固综合地层处置措施有效,可为类似工程提供借鉴。

Based on the large diameter shield of Suzhou Tongjing Road North Extension project undercrossing the bridge pile foundation of Shanghai-Nanjing high speed railway,the numerical simulation was carried out on the integrated stratum reinforcement treatment of isolation pile combined with MJS(Metro Jet System)grouting before shield undercrossing.The shield active construction control measures of the undercrossing process were also verified in practice.The results show that,the displacement of the bridge pier can be effectively controlled by the isolation pile combined with MJS grouting reinforcement,and can be reduced to 6%~10%of that without taking measures,which meets the control requirement of 2 mm.Combined with the shield active construction control measures,such as excavation parameter control and injection of clay shock synchronously,the displacement of bridge pier is stable during the shield undercrossing,and the measured maximum displacement in each direction does not exceed 0.5 mm.These prove that the measures in this paper are valid and can provide reference for similar projects.