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 an nominally 20.5 m wide and 159 m long cavern opening up from the eastern side of the station box, which consist of two parts:
And a 2.5 m long transition section between these parts
The cavern finishes with a headwall from where it connects to two smaller stub tunnels.
The 500 mm thick cavern lining is reinforced up the construction joint above the lower wall.
The walls and crown lining above this level is 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.