4.5 km Weinberg Tunnel

The Weinberg Tunnel, part of Section 3 of the cross-city link in Zürich, is a two-track railway tunnel that stretches 4,537 metres from the southwest section to the portal in Oerlikon. This project comprises Lots 3.1 and 3.2, with Lot 3.1 involving the southern section shaft and the extension to the new train station, and Lot 3.2 encompassing the 40-meter-deep Brunnenhof shaft, the Weinberg Tunnel, and the rocky stretch between Brunnenhof and the Oerlikon portal. It also includes escape and rescue tunnels with cross-passages.

Advanced TBM and Hydroshield Techniques

Advanced tunneling techniques were employed across the project, including the use of TBM for 4,134 metres of hard rock and hydroshield technology for the final 246 metres. Dual-shell reinforcement was applied to the extension, using 30-centimetre-thick reinforced concrete segments for the outer shell and non-reinforced in-situ concrete for the inner shell. Certain tunnel sections required increased concrete segment thickness to 60 cm at the base, with added reinforcement in areas surrounding cross-passages.

Concrete and Excavation Management

Key operational strategies included converting from TBM in hard rock to hydroshield technology, traversing the Limmat River with pipe umbrellas, and managing a dedicated concrete station at the Brunnenhof installation site, producing a total of 55,000 cubic metres of concrete. The management and disposal of excavated material were critical components, along with freezing techniques employed for sealing off the southern section shaft with liquid nitrogen between the old and new diaphragm wall.

Key Players and Timeline

The project involved several key players, including Schweizerische Bundesbahnen as the building owner, IG Zalo c/o Basler & Hofmann AG as the project designer, and TBM Tunnelling overseeing construction management. Commencing in January 2007, the project was completed in January 2013 with a construction volume of 353.6 million CHF.