Cooksley Street tunnel bore
As part of the Kingsford Smith Drive upgrade, underground services including stormwater will be relocated and upgraded. At Albion, a new underground stormwater drain will be installed beneath Cooksley Street and Kingsford Smith Drive.
Conventional construction methods to install the new stormwater pipe would have required major excavations, traffic lane closures and weeks of consecutive night works. Additionally, there are 27 other underground services that would need protection or relocation if the new drain were to be installed by trenching.
To minimise impact on the community and disruption to services, the new stormwater pipe will be installed using a tunnel boring machine (TBM). The TBM performs two main tasks:
- excavating rock and soil with a rotating cutter head at the front of the machine before it is transported behind the TBM
- progressively lining the tunnels with pre-cast pipe segments to support the ground and form the new stormwater line.
As the TBM allows the installation of the new stormwater pipe to be completed underground, there will be a reduced disturbance to the surrounding ground and underground services when compared to conventional trenching methods.
Tunnel bore process
The tunnel bore process is comprised of several steps:
Step 1. Launch shaft construction and installation of TBM
A six-metre-deep reinforced concrete circular shaft was constructed at Cameron Rocks Reserve to launch the TBM.
Step 2. Tunnel bore and pipe jack
The machine will bore a distance of 106 metres beneath Kingsford Smith Drive, with the tunnel 4.5 metres at its deepest point.
Simultaneously, stormwater pipe will be hydraulically jacked (pushed) from the launch shaft, so that it forms a continuous pipe underground. The pipe, which is specially designed to withstand the jacking forces encountered during installation, will form the final stormwater pipe. The machine will push 39 segments, each at 2.75 metres long to form the new stormwater pipe.
Step 3. Retrieval of TBM
After reaching its destination, the machine will be retrieved by excavating a large pit in Cooksley Street. At this point, the newly installed stormwater pipe will be connected to the existing line.
|Internal diameter||7.5 metres|
|Number of segments||4 lifts|
|Length of segment||2.75 metres|
|Diameter of segment||2.05 metres|
|Number of segments||39|
|Deepest point||4.5 metres|
Working with the community
Lendlease is committed to minimising impacts on local residents during construction of the Kingsford Smith Drive upgrade and we look forward to working with you throughout construction.
If you would like more information regarding tunnel boring activities, please contact the Community Relations Team on 1800 084 383 or email firstname.lastname@example.org