隧道净距离上下交叠设计施工处治措施

Design and Construction Measures for Clear Distance up-and-down Crossing Tunnels

龙洲湾2#公路隧道上跨铁路隧道,并在洞口段上下呈小净距交叠,最小净距约4.5 m,且2#公路隧道先于铁路隧道施工。为最大程度降低2隧道施工时的相互影响,通过加强交叉段隧道衬砌结构设计参数、在2#公路隧道内预留扩大断面和增加变形缝、铁路隧道采用洞内管棚及控制爆破的设计施工方法,同时加强施工监测等工程措施,并用FLAC 3D数值计算方法对公铁隧道交叉段进行三维有限元分析。计算结果表明,经过处理措施后,2#公路隧道的沉降能够控制在安全范围内,控制爆破最大限度减小双洞相互影响。铁路隧道施工时采用实时监测,现场建立公、铁双方施工联动沟通机制及时互通信息,可确保施工安全。

The Longzhouwan 2^# highway tunnel crosses the railway tunnel and overlaps at a clear distance crossing between the upper and lower sections of the tunnel. The minimum clear distance is about 4.5m, and the 2^# highway tunnel precedes the construction of the railway tunnel. In order to minimize the mutual influence of the tunnel construction, the design parameters of the lining structure of the tunnel in the cross section are strengthened, the enlarged section and the deformation joint are reserved in 2^# highway tunnel, the design and construction methods as the tunnel shed in the tunnel and the controlled blasting are adopted, at the same time, construction monitoring and other engineering measures are strengthened. FLAC3D numerical method is used to analyze the mutual influence .The calculation results show that the settlement of 2^# road tunnel can be controlled within the safe range after the treatment measures, and controlled blasting greatly reduces the interaction . To ensure construction safety, real-time monitoring is adopted during the construction of railway tunnels, and information can be received in time because of the construction linkage communication mechanism between the two sides.