By rosebell
While the cavern lining has been completed, the process of retrievaling two TBMs is undergoing at Sydney Metro West’s Westmead station.
Excavation of the Sydney Metro West tunnels from Sydney Olympic Park, through Parramatta, was up to TBMs Betty and Dorothy and they made their final breakthroughs at Westmead in September and October respectively.
As an autonomous TBMs that is equipped with AI software capable of automatically steering, operating and monitoring the machines, this 9km journey was the first in Australia.
Benefiting a 750-tonne mobile crane, the 1,200-tonne TBMs are now being dismantled and lifted to the surface.
Over a time period of almost seven weeks, these TBMs are being transported in sections through the crossover cavern to the station box, and lifted out in pieces of varying sizes.
With the aim of refurbishment and reusing on other projects, key components of the TBMs such as the main drives will be recovered and the remaining parts are due to be recycled.
As a process that required construction of the largest formwork system of its kind in the southern hemisphere, the cavern wall lining has also been completed.
The process of jacking and winching the temporary arch into position with millimetres to spare was done by crews in an 82-hour operation, whereas once the structure was in place, the team completed a 1,941-tonne concrete pour to create the cavern’s 2.5m-thick walls.
In order to building the 21m-high structure, almost 12 months of planning and collaboration, along with multiple crawler cranes was needed.
With around 26m high,the tallest cavern on the Sydney Metro network is fully lined with completing the formwork operation now. Tunneling at the eastern end is approaching its final breakthrough to Hunter Street in Sydney’s CBD, with TBMs Ruby and Jessie now less than 550m from completing the 24m twin tunnels.
