NorthConnex tunnel

In Australia, north of Sydney, Bouygues Construction Australia designed and built a 9-kilometer-long, 2x3-lane highway tunnel connecting the M1 and M2 highways. Every day, thousands of heavy trucks are diverted from Pennant Hills Road, a congested urban thoroughfare, helping to ease traffic flow, reduce congestion, and limit air pollution in the city center.

As the backbone of northern Sydney's mobility, NorthConnex is helping to transform the quality of life for residents by improving travel, enhancing road safety, and optimizing connections between the north and west of the city.

To overcome Sydney's geological challenges, the NorthConnex excavation project mobilized a fleet of roadheaders, mechanical excavation machines equipped with a large rotating cutter head mounted on an articulated arm. Unlike traditional tunnel boring machines, these machines offer great flexibility on short sections and complex routes, while adapting perfectly to the sandstone terrain encountered.

Their ability to gradually “nibble” away at the tunnel face ensured safe, controlled and highly accurate excavation in an urban environment.

Topographical surveys were carried out using scanners and transmitted via Wi-Fi to the surface. The holes for fixing the tunnel equipment supports to the ceiling were drilled by the Roby 850 robot.

These technical choices illustrate Bouygues Travaux Publics' expertise in adapting its excavation methods to local contexts, combining innovation, operational efficiency and respect for the environment.