ABSTRACT
Forrestfield Airport Link Project foresees the extension of the existing urban railway network in Perth through 8.5 km twin bored tunnel crossing the airport land and with three new stations. The new railway will allow a 20 minutes journey into the Perth CBD from Forrestfield Station and improve bus network from the surrounding community. The two TBM’s crossing underneath the Airport runways was a delicate point for the Client, reason why it required a Variable Density TBM, supplied by Herrenknecht, capable to operate in Slurry and EPB mode, based on the variable geological conditions. During the machines design phase, Salini-Impregilo decided to not install the conveyor belt and evacuate the spoil material via the slurry pipes system even when excavating in EPB mode. It’s the first time that Salini- Impregilo operates this kind of machines and the scope of this article is to illustrate their complexity and operation modes.
