Land Transport Authority
ER296 – Construction and Completion of Sentosa Gateway Tunnel and Associated Road Widening Works along Lower Delta Road
Sentosa Gateway Tunnel was a highly complex project due to its close proximity to the tunnels of North-East MRT Line and foundations of West Coast Highway viaduct. Other challenges faced by the project include large scale diversion of underground services by phases, construction of tunnel under heavy live traffic and a low tunnel height limit of 3.8 m.
The project team overcame these site constraints by working on highly efficient construction planning, strategic work sequences and innovated machineries and vehicles. To minimize disruption to the live traffic, construction methods of top-down, bottom-up and pipe-box tunnel (PBT) were adopted. During the process of tunnel construction, diaphragm wall (D-wall), steel strutting and RC walers systems were deployed to retain and stabilize the adjacent earth.
The entire project encompassed works such as the construction of pipe-box tunnel, cut-and-cover tunnel and contiguous bored pile (CBP) walls, diversion of sewer lines, road widening and the erection of a 3-storey facility building.
Adoption of semi-top-down RC walers system has significantly reduced the construction duration of this project.