ABSTRACT
The existing Gotthard Road Tunnel is one of the most important underground connections in Europe. With a total length of 17 km across the Alps, it connects the German-speaking northern part of Switzerland to its Italian-speaking southern part. After more than 40 years of operation, the existing tunnel must be renovated. In order to avoid interrupting this crucial north-south link, the Swiss electorate decided to build a second tube to ensure road traffic during renovation work of the existing tunnel. The project of the second tube of the Gotthard Road Tunnel includes the construction of a new two-lane tunnel parallel to the existing tube, 5 new underground ventilation caverns, 2 new technical buildings at the tunnel portals and new cross-passages to the existing tunnel every 250 m. Prior to the excavation of the second tube tunnel, numerous underground preparatory works will be carried out, such as two access tunnel of 5 km length each, and two new sections of the service and emergency gallery. The present paper highlights different design aspects of these preparatory works and lessons learned after about two years of construction in the heart of the Alps.
