The retrieval of tunnel boring machines (TBMs) Betty and Dorothy has begun following their journey to construct part of the tunnels making up the Sydney Metro West project.
The two TBMs carved out tunnels departed from Sydney Olympic Park, excavated through Parramatta, and arrived at Westmead in September and October respectively.
Setting out to carve 9 kilometres of tunnel; the journey was the first in Australia to use autonomous tunnel boring machines equipped with artificial intelligence software, allowing the two TBMs to be steered, operated and monitored automatically.
Now, following the journey’s completion, the two 1,200-tonne TBMs must be lifted from the ground – piece by piece – using a 750-tonne mobile crane.
The process begins underground, as each TBM is dismantled before being lifted out in pieces of varying sizes and shapes.
Larger components, such as the 100-tonne cutterheads and 110-tonne main drives, are retrieved via the use the aforementioned crane, whilst other pieces will be lifted over multiple loads using a gantry crane.
All key components of the TBMs, such as the main drives, will be recovered for refurbishment and reuse on other TBM projects. The remaining parts will be recycled.
