Work is ramping up in the Hunter Street Station cavern – Sydney CBD’s deepest underground structure – as it prepares to welcome two tunnel boring machines on their way from Pyrmont.
28,192 tonnes of concrete have been poured to form the cavern floor, a complex task completed over three months.
The team has commenced with lining and waterproofing the huge 180 metres long by 28 metres wide by 20 metres high cavern and 1.2-kilometre turnback tunnels.
The turnback tunnels extend beyond the Hunter Street platforms and are a key piece of the line as they will allow trains to turn around after reaching Hunter Street and head back towards Westmead.
Lining works over the next 14 months will require more than 12,000 tonnes of reinforcement. This will be locked in place with 110,184 tonnes of concrete and then covered with 50,129 square metres of waterproof lining.
About 38 per cent of the lining work has been completed to date.
Elsewhere in the cavern, two shafts connecting to the surface are being excavated. These will be the entry/exit points for the future station.
Around 230 workers are on site at Hunter Street each day, working around the clock, to deliver these important cavern works. The cavern is due to be completed in late 2026.
TBMs Jessie and Ruby are currently undergoing maintenance in Pyrmont after their double breakthrough on 10 July. In the coming weeks, the tunnelling machines will begin the final 1.1-kilometre journey beneath Darling Harbour to Hunter Street.
The breakthroughs at Hunter Street will be the last for the Sydney Metro West project, which is currently around 90 per cent through tunnelling.
