A4/A20 Uetliberg Tunnel, Birmensdorf

Part of the A4/A20 Zurich west bypass. Two parallel tunnels each 4,400 m in length. Unconsolidated rock: Gjuch 200 m, Diebis 230 m, Juchegg 390 m. Molasse sections: Eichholz 510, Uetliberg 2790 m. Cut-and-cover section 230 m with Reppichstal ventilation station. Cross-over points every 290 m, of which 3 navigable by traffic, 10 by pedestrians.

Heading of a pilot gallery with a 5.0 m diameter tunnel boring machine followed by a tunnel expansion machine (TBE 14-14.4 m diameter). Unconsolidated sections before the molasse section created using the German (core-leaving) method.


Specific figures

Order value

CHF 375 million

Construction period

2000 - 2006


8800 m

Total excavated surface

148 m2