By Lynda Myer
In order to advancing the 24-km Sydney Metro West project between Westmead and the Sydney CBD, the last two of six TBMs with 1.3t weight have successfully completed their Factory Acceptance Tests. The intended machines which are mixed shield slurry TBMs and suitable in softer ground conditions and high-water pressures , are ideal for tunneling beneath the harbour.
The commissioning process of the two new TBMs has started by preparing the 32-m-deep station box at the eastern end of The Bays site, whereas the date of carving out the 3.5-km twin tunnels from The Bays, under Darling Harbour, to Hunter Street in the Sydney CBD will be the mid-2024.
Also construction process of the Sydney Metro West tunnels is powering ahead in deep underground using four of six TBMs in the ground.
Considering that TBMs Daphne and Beatrice have to continue their journey to Sydney Olympic Park, in the next weeks they are going to be prepared and re-launch from Five Dock Metro Station. Next stop for the TBMs is the Burwood North Metro Station site around 2 km away, where they are due to arrive in early 2024.
Being started up from the western side of The Bays station box in December 2023, the TBMs Beatrice and Daphne broke through at Five Dock Metro Station, while initially TBM Daphne broke through, followed closely by TBM Beatrice, after building the 4.3-km section of metro tunnel from The Bays to Five Dock for around seven months and installing approximately 30,732 segments to line the new tunnel walls.
The quantity of dug material by these huge machines was 437,463 t and the 22 m wide and 30 m deep Five Dock station cavern was excavated with about 286,047 t of material removed.
With a acceptable progress on their journey, TBM Betty and TBM Dorothy that are the first autonomous TBMs to be used in Australia launched from the Clyde launch box and are tunneling almost 180 m a week and are expected to complete the first 4.5-km leg of their journey and arrive at Sydney Olympic Park in mid-2024. The TBMs are installed with artificial intelligence software, which has the capability to automatically steer, operate and monitor the machine.
TBM Dorothy has been named in honour of Dorothy Buckland-Fuller who was an Australian human rights and founded the Australian Migrant Women’s Association.
TBM Betty was named after Olympic champion Betty Cuthbert who attended Parramatta Home Science School (now Macarthur Girls High School).
In order to lining the 24-km Sydney Metro West tunnels, thousands of precast segments are being manufactured in western Sydney, while the Eastern Creek Precast Facility is made up of three huge sheds, each with its own production line, and was purpose-built to support construction of the new metro line that will connect Greater Parramatta to the Sydney CBD. A total of 61,000 of almost 150,000 precast segments, weighing 3.5 t each, have been produced at the facility since it opened late last year, with operations continuing around the clock from Monday to Saturday and maintenance work on Sunday.
The daily production of segments at the facility is approximately 500 and they stored in the yard, before being transported to the appropriate site for loading onto one of the operational TBMs. The TBM then installs the segments to the tunnel walls as it excavates forming the rings that line the tunnels
