A second TBM has officially begun tunnelling at Forrestfield, as part of the $1.86 billion METRONET Forrestfield-Airport Link project.
TBM Sandy was launched from the 12-metre-deep dive structure at the site of the future Forrestfield Station today. Sandy – named by High Wycombe Primary School Year 4 student Sarah Spratt – is named after the local digging insect the ‘Sandgroper’.
TBM Grace, named after local schoolgirl Grace McPhee, was launched on July 30, starting a two-year journey to Bayswater where the 8.5-kilometre Forrestfield-Airport Link will spur off the Midland Line.
Grace began tunnelling in earnest in August, and has now travelled around 620 metres in to the earth. The machine is currently travelling around 20 metres per day.
The two TBMs will each tunnel eight kilometres under Perth Airport and the Swan River, linking new stations at Forrestfield, Airport Central and Belmont.
Construction of diaphragm walls (which will house the station box structure) is now complete at Airport Central, and excavation of the soil inside the walls has begun. Diaphragm walls are also under construction at Belmont, and are about 70 per cent complete.
As the TBM cutter heads bore through the earth, the machines will also install about 54,000 reinforced concrete tunnel segments, and now that the two TBMs have launched, segment production has ramped up.
About 5,750 segments of the 54,000 needed to complete the tunnel structure have already been fabricated at a local Forrestfield segment facility.
More information is available at www.forrestfieldairportlink.wa.gov.au