The $8.3billion North West Rail Link project is the longest transport tunnelling project in Australia’s history and is expected to be complete by 2019. The 15 km long twin tunnels are being constructed to connect Sydney’s northwest suburbs to the city for the very first time.
The Cross-Over Cavern at Castle Hill is 20.5 m wide and 159 m long, with the cavern opening up to the eastern side of the station box, consisting of two different cross-sections:
The cavern terminates with a headwall where it connects to two smaller bored tunnels.
The 500 mm thick cavern lining is reinforced up to the construction joint above the lower wall, at the widest part of the cavern.
The walls and crown lining above this level are unreinforced.
The between 800 mm and 1200 mm thick headwall is completely reinforced
Thiess John Holland Dragados JV
The assistance provided by PERI in coordinating the design requirements, the methodology and subcontractor suggestions, was integral to the success of the project.
When assembled onsite the mechanical nature of the form removed many manual handling and work at height risks, whilst the drive units allowed the unit to be propelled in a safe and timely manner, allowing further safety and program improvements.