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Two of the biggest tunnelling machines in the world are about to make the marathon journey from China to Sydney to carve out the city’s second harbour road tunnel.
A job triple the size of the metro means much bigger hardware and 9News can reveal the monster machines for the first time.
The two biggest tunnel boring machines in the Southern Hemisphere are right now being pulled apart in China and fitted for a journey under Sydney Harbour to build the Western Harbour Tunnel.
“It’s going to be the equivalent of three Sydney Metro tunnels so it’s quite large and we need a large machine to do that work,” NSW Roads Minister Jenny Aitchison said.
The mega machines are 102 metres long, almost 16 metres wide and weigh nearly four and half tonnes.
The heavy weight have been hauled in specifically to chew through 1.5 kilometres of Sydney sandstone, 50 metres under the harbour.
Each will excavate a tunnel wide enough for three lanes of traffic, completing the underwater section of the Western Harbour Tunnel between Birchgrove and Waverton.
Camilla Drover, Deputy Secretary Infrastructure Projects and Engineering for Transport for NSW explained how it’s set to be a much higher tech process than was used 30 years ago constructing the first harbour tunnel.
“They not only cut and excavate, they line the tunnel as they go, so 10 concrete segments will form a full ring for each segment so that 13000 concrete slabs,” she said.
“We actually made concrete tubes and had to float them in and dredge the harbour and drop them into place.”
The machines are due to arrive at Glebe Island in the next few months.
It will then take another couple of months to re-build both machines underground in their launch chambers.
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Once they start, they won’t stop, tunnelling 24/7 with 40 people on shift at all times.
The historic journey is expected to take around a year to complete.
Finishing touches are expected in 2028, connecting the city’s north to the inner west.
“It will cut travel times but most important thing we will ease congestion and lose that frustration,” Aitchison said.
