重叠隧道施工中大轴力桩基主动托换技术

 由于受到环境条件的限制，深圳地铁一期工程3C标段（国－老区间北段）暗挖单洞重叠隧道需要穿越高层建筑物。在施工过程中，对隧道通过区段的桩基采用主动托换技术，需要托换的桩的最大轴力为1800t，施工难度和风险很大，为了保证建筑物安全，采取了合理的施工方案和工程措施，就重叠隧道施工中桩基的主动托换施工技术进行介绍。

Construction Technology for Active Underpinning of Pile Foundations with Huge Axial Forces Applied in Construction of Overlapping Tunnels

Due to the environmental constraints, the Overlapping single-tube mined tunnels of 3C contract section of phase 1 of Shenzhen Metro, i.e. the north portion of Guo-Lao section, go through underneath the high building of Baihuoguangchang. During the tunnel construction, active underpinning construction technology is adopted for the pile foundations under which the tunnels go through. Due to the 1 800 t maximum axial force of the pile foundations to be underpinned, there exist great construction difficulties and great risks. Proper construction schemes and engineering countermeasures are taken in order to ensure the safety of the building. The paper presents the construction technology for the underpinning of the pile foundations applied in the construction of the overlapping tunnels.