By rosebell
Considering that Hunter Street Station cavern is prepared for the arrival of two TBMs, work is in full swing inside Sydney CBD’s deepest underground structure.
On July 10, at the Pyrmont Station cavern a double breakthrough was made by TBMs Jessie and Ruby, and currently they are undergoing maintenance before they begin the final 1.1km journey beneath Darling Harbour to Hunter Street.
In order to forming the cavern floor, a complex task completed over three months, 28,192 tonnes of concrete have been poured at the Hunter Street Station cavern, whereas lining and waterproofing the 180-long, 28m-wide and 20m-high cavern and 1.2km-long turnback tunnels has been commenced by the team.
As the turnback tunnels allow trains to turn around after reaching Hunter Street and head back towards Westmead, they extend beyond the Hunter Street platforms and are a key piece of the line.
Requiring over than 12,000 tonnes of reinforcement, the lining works will take 14 months and this is due to be locked in place with 110,184 tonnes of concrete and then covered with 50,129m2 of waterproof lining, while around 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.
While the scheduled date for completing cavern is late 2026, almost 230 workers are on site at Hunter Street each day.
The breakthroughs at Hunter Street will be the last for the Sydney Metro West project, for which around 90% of tunnelling is complete.
