Work is in full swing inside Sydney CBD’s deepest underground structure, as Hunter Street Station cavern is prepared for the arrival of two TBMs.
TBMs Jessie and Ruby made a double breakthrough at the Pyrmont Station cavern on July 10. They are now undergoing maintenance before they begin the final 1.1km journey beneath Darling Harbour to Hunter Street.
At the Hunter Street Station cavern, 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 180-long, 28m-wide and 20m-high cavern and 1.2km-long 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 50,129m2 of waterproof lining.
About 38% 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. The cavern is due to be completed in late 2026.
The breakthroughs at Hunter Street will be the last for the Sydney Metro West project, for which around 90% of tunnelling is complete.
