Steel Immersed Tube Tunnels where Tunnel Boring Machines Cannot Operate – Yarra River Crossing Construction on the Melbourne Main Sewer Replacement Project

摘要

The Melbourne Main Sewer Replacement (MMSR) is a major urban infrastructure project involvingrnapproximately 2.3 km of tunnelling and construction works. The works extend from DocklandsrnPrecinct, on the southwest edge of the city, southwards to connect with the Hobsons Bay Main Sewerrnin Port Melbourne. The tunnel boring machine (TBM) tunnelled section of the works terminates at thernYarra River where the delta geology and alignment requirements precluded the use of undergroundrntunnelling methods. The 132 m long river crossing works involve a cut-and-cover excavation withinrna staged fl ooded cofferdam construction to construct an immersed tube tunnel as an extension of thernTBM works.rnThis paper reports on the development of the staged construction method and highlights therngeotechnical and structural design aspects involved in building a new sewer in the Yarra River tornclose the gap between the new TBM driven and pipe-jacked tunnels.