Durchmesserlinie Rail Project Milestone: Weinberg Tunnel Breakthrough
A key milestone in the Durchmesserlinie cross-city rail link project was reached on Monday, November 22nd. After two years of construction work, the tunnel boring machine’s (TBM) breakthrough was celebrated under Zurich's main rail station. Geological conditions posed major technical challenges for the Weinberg Tunnel project. This successful completion will be remembered in the annals of tunnelling as a significant, pioneering achievement.
A series of critical challenges had to be overcome during the planning and construction of the Weinberg Tunnel. For example, the tunnel emerges from the rock on the right bank of the river Limmat into loose rock below the groundwater table. It then passes virtually underneath Zurich's historic main rail station hall and emerges into the new underground through-rail station at Löwenstrasse. Complex construction measures, such as a large pipe screen and extensive injections, made it possible to guarantee safety in these areas. The tunnel also passes a short distance below several buildings that are used for sensitive purposes, such as the DRS radio studio.
Tunneling work was started with the TBM in October 2008. Advancing at an average rate of 20 metres per day, the TBM was operated in what is known as a mix-shield mode from the Brunnenhof tunnel in Oerlikon towards the main station. After some 4.2 kilometres of tunnelling, the machine reached the river Limmat in summer 2010. At this point, the TBM was fitted with a hydroshield so that it could safely bore the remaining 280 metres through loose rock in the groundwater.
The Weinberg tunnel was planned and designed by the Zalo Engineering Consortium (IG) (Basler & Hofmann, Pöyry Infra and SNZ) with Basler & Hofmann as the project lead.
Weinberg Tunnel Data
Client: SBB AG
Length: 4.42 km, including 280 m through loose rock
Diameter: 10.90 m
Execution of construction work: 2007 - 2013
Commissioning of tunnel: mid-2014
Services provided by Basler & Hofmann
Construction project / regulatory approval project
Detailed design / execution project
Public relations work