OUR PROJECTS

Providing the Complex Infrastructure Needed to Build Better Communities

Tunnel Boring Machine in shaft about to drill tunnel

finished tunnell prior to cabling being installed

Burrows Road Tunnel

Abergeldie constructed an underground cable tunnel beginning in Campbell Road, running below Burrows Road, and finishing at the Energy Australia (EA)/ Transgrid substation in Alexandria. The tunnel carries 6 x 132kV circuits.

The project featured a launching shaft, an 87m long, 2800mm diameter, pipe jacked tunnel and a receiving shaft. The receiving pit featured 2 stages of construction, a temporary shaft to allow for the removal of an EPBM and further modifications to construct the final pit which sits within the EA boundary of the new substation.

Client

Energy Australia

Year

2010

Region

NSW

Tunnel Length

Tunnel Diameter

Within Specified Alignment

Scope of Works

Complexity

Soil conditions presented extreme challenges. The tunnel alignment is beside the Cooks River industrial canal and below the water table for its entire length. The launch and receive shafts needed to be dewatered constantly, with water pumped to tanks for treatment. Extreme care was taken with grouting and jointing of pipe sections to ensure that the finished pipeline was completely watertight, to enable safe installation of High Voltage cables.

Steering of the pipe jack rig in very soft soil demanded close monitoring and frequent small adjustments to maintain level and alignment. The finished tunnel was within 7mm of the specified alignment, well within the allowed 20mm tolerance.

The large number of buried and overhead services in the area required close and frequent consultation with multiple authorities, including Sydney Airport. As the site was directly under the main runway landing flight path, prior notice and approval was required for all crane lifts.

Traffic management and community liaison were also high priorities. The immediate area is densely developed with both industrial and residential properties, and one of the pits had to be sunk in the middle of a road intersection.

Community Benefits

Because trenchless construction was used to construct the tunnel, there was significantly less disruption to traffic and the construction site itself operated with significantly less noise than would have occurred had open trench methods been used.

Access to the nearby Sydney Park, the largest community open space in the district, was unaffected during construction.

The community also benefits from improved power utility infrastructure which facilitates delivery of more electricity for the local community and industry.