Behind the scenes of the massive set-up work for of 24/7 tunnelling operation for South Rd’s River Torrens to Darlington upgrade
SA’s biggest construction project on record started in May – and a behind-the-scenes look revealing its staggering scale must be seen to be believed.
A construction manager for the $15.4bn South Rd upgrade – South Australia’s biggest ever construction project – has described the staggering scale of manpower and materials already seen in the project’s preparatory phase ahead of the creation of tunnels.
Works began in May to prepare for the arrival of three tunnel-boring machines (TBMs), which will be used to create a much-hyped “non-stop South Rd” stretching 78km between Gawler and Old Noarlunga.
Stefan Sorani, a construction manager at the project’s southern precinct, said the TBMs would be among the world’s biggest at 100m in length and 15m in diameter.
“The fact we’ve got three of them on one project, it’s rare to have that even in projects around the world – so, this a big project even on an international scale,” he said.
“It’s the biggest project I’ve ever worked on – just massive scale.”
The works, which already involve hundreds of workers across day and night shifts, are set to ramp up and become 24/7 when tunnel-boring starts in the second half of next year.
Mr Sorani said the tunnelling “doesn’t stop once it starts”, progressing about eight to ten metres a day, and his work now was setting up this massive tunnelling operation.
He said 150 workers were on his southern precinct site on Friday – not including those at the northern precinct – and the number would reach 550 at the peak of construction.
The TBM components, purchased from a German manufacturer, are set to arrive later this year by ship at Port Adelaide from China, where they are being assurance-tested.
“We have a very, very tight program to be ready for the TBMs,” Mr Sorani said.
“The amount of things we need to get in and out is probably more than what people would think. We do about 200 truck movements a day just to get material in and out to keep the site going.
“At the moment, we’re doing a 300-cubic-metre concrete pour. That’s about 60 concrete agis (agitator trucks) that have to come in and out of the gates. There’s 10 trucks of reinforcement every day. We have to get rubbish trucks in and out.”
As of the end of August, almost 16,500m3 of concrete and more than 4500 tonnes of steel had been used to construct underground diaphragm walls to form a “launch box” to support the TBMs.
“You don’t see a whole lot happening above ground, because at the moment everything’s been done below ground with 25m deep piles or diaphragm walls up to 40m deep,” Mr Sorani said.
Mr Sorani oversees the southern precinct at Clovelly Park, the most progressed of the project’s three construction sites, where two TBMs will be launched.
Another will launch at the central north precinct between Hilton and Richmond, and the TBMs will finish excavating the southern tunnels at the central south precinct, which is still undergoing early site establishment works.
The removal of ground materials from the tunnels – known as spoil – will be another huge undertaking, with more than 7.5 million tonnes to be removed over the whole project.
The project is set to support 5500 jobs a year during the main construction period before the road’s planned opening to traffic in 2031.
The 4km southern twin tunnels and 2.2km northern twin tunnels will let motorists bypass 21 sets of traffic lights between the River Torrens and Darlington.
Transport Minister Tom Koutsantonis said the project was “massive but necessary” as the “arteries of our existing grid network are hardening”.
“We are the last capital city on the mainland to be operating on a grid network, without a non-stop corridor going through it,” he said.
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Originally published as Behind the scenes of the massive set-up work for of 24/7 tunnelling operation for South Rd’s River Torrens to Darlington upgrade
