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Giant Tunneling Machines Carve Under Sydney Harbour
10 Aug
Summary
- Two massive 4400-tonne tunneling machines are digging 1.5km under Sydney Harbour.
- The project uses hyperbaric chambers as a precaution against deep-sea pressures.
- The new motorway tunnels are large enough to fit three metro rail tunnels.
Two massive 4400-tonne Tunnel Boring Machines (TBMs), named Barangaroo and Patyegarang, are currently excavating twin tunnels for Sydney's $7.4 billion Western Harbour Tunnel motorway. Operating with laser-like precision, these machines are creating passages up to 47 meters below the harbor's surface, with each tunnel wide enough to accommodate three metro rail tunnels.
The TBMs are progressing through challenging sections, including a 200-meter paleo channel filled with clay, silt, and sand. To mitigate risks associated with the high pressures encountered, hyperbaric chambers are on standby. Acciona, the Spanish contractor, is managing the project, which involves up to 600 workers underground.
The 6.5-kilometer motorway is over half complete and is slated to open in late 2028. It aims to significantly reduce traffic congestion by providing an alternative to the Sydney Harbour Bridge and Tunnel, connecting the Warringah Freeway to the WestConnex toll road.
The boring machines are the largest in the Southern Hemisphere, featuring a 15.71-meter cutting diameter to accommodate three lanes of traffic. Their progress is meticulously tracked, with concrete segments fitted to line the tunnels to millimetre accuracy, showcasing the project's commitment to precision engineering.
