Tunnel Boring Machines
Tunnel Boring Machines (TBMs) are large machines that excavate below the ground surface, while simultaneously installing concrete lining units to build a tunnel. Two TBMs have been specifically designed for the Forrestfield-Airport Link by German company Herrenknecht, the world’s leading supplier of TBMs.
There are various types of TBMs to cater for different ground conditions and project requirements. For this project, the TBMs will be Mixshield, which use the latest dual-mode technology capable of adapting to variable ground conditions (such as sand, rock and clay) as the machine progresses.
Key components for our TBMs were manufactured in various places around the world before an in-depth nine-month assembly and testing program was conducted in China. Once testing is finished, they are disassembled and shipped to Henderson Port.
The first of the TBMs will soon begin its shipping journey to Perth, with the second due to arrive on site at Forrestfield later this year. The TBMs will be lowered into a dive structure and begin their two-year journey towards Bayswater. During this 8km journey, the TBMs will excavate under Perth Airport and the Swan River reaching up to approximately 25m depth below the surface.
Once tunnelling begins the TBMs will be in operation 24 hours a day. They will be staggered two months apart to help ensure ground stability.
To find out more about how these machines operate, view the TBM fact sheet.