Australia's North East Link Completes 58 Tunnel Arch Lining Pours

en.Wedoany.com Reported - On September 10, all final arch lining construction was completed for the sequential excavation method (SEM) tunnels of Australia's North East Link project. The two SEM tunnels each completed 29 arch lining concrete pours, totaling 58, marking the completion of all arch structures in the permanent lining of this tunnel section. Webuild is participating in the design and construction of the North East Link tunnels as a member of the Spark consortium.

The arch lining construction used two sets of steel formwork trolleys weighing approximately 320 tonnes each. Each trolley supports approximately 364 cubic meters of concrete per pour, with a single continuous construction period of approximately 18–20 hours. This equipment is used to form the tunnel's final wall and crown structures and is the core large-scale formwork system for SEM permanent lining construction.

In April of this year, the project had already completed its 58th and final tunnel invert pour. Since the first invert was poured in September 2025, the SEM tunnels had completed a cumulative 118 permanent lining pours as of that time, using more than 21,000 cubic meters of concrete and nearly 5,000 tonnes of reinforcement steel. After the invert was completed, construction continued with backfilling, the kicker walls on both sides, and arch lining; in September, all 58 arch pours were completed, further closing the SEM tunnels' permanent main structure.

After the invert structure was completed, backfilling was required above it and connection with the kicker walls on both sides to create structural conditions for road base construction. In April, kicker wall construction had advanced along the alignment and prepared working faces for subsequent arch construction; with all arch lining now completed, construction in this tunnel section will continue to shift to road structures and subsequent mechanical and electrical works.

North East Link has previously had TBM tunnels, invert, and other individual construction milestones. This is not the project's "first breakthrough" or overall tunnel completion, but rather a new construction milestone marking the completion of all 58 final arch lining pours for the SEM tunnels.