Industry Infrastructure, Passenger Rail, Rail industry news (Australia, New Zealand), Tunnelling

Sydney tunnel boring breakthrough a record feat

sydney tunnel boring


Two tunnel boring machines (TBMs) have broken through a rock wall to arrive at Five Dock Metro Station in Sydney, claiming the title as the first TBMs in the southern hemisphere to complete a double breakthrough.

The TBMs are powering ahead to build twin 24-kilometre metro tunnels between Westmead and the Sydney CBD as part of the Sydney Metro West project.

TBM Daphne broke through first, followed closely by TBM Beatrice, after building the 4.3-kilometre section of metro tunnel from The Bays to Five Dock for around seven months.

The two 1300-tonne tunnel boring machines will spend the next few weeks traversing to the western end of the station cavern. During this time, the machines will undergo all necessary maintenance before being relaunched to continue their journey to Sydney Olympic Park.

To date, the huge machines have excavated a total of 437,463t of material each and installed about 30,732 precast concrete segments to line the new tunnel walls.

To prepare for the arrival of the TBMs, the Five Dock station cavern was excavated with about 286,047t of material removed to create the underground box-like structure that is 22 metres wide and 30 metres deep.

Next stop for the TBMs is the Burwood North Metro Station site about two kilometres away, where they are due to arrive in early 2024.