A9 Visp south bypass Eyholz tunnel

The Eyholz Tunnel represents the eastern part of the Visp bypass and consists of two tubes, each 4,255 m long and connected at regular intervals to transverse tunnels that can be traveled on foot and by vehicles. The work also includes two branch caverns, access and exit tunnels as well as ventilation stations at the two portals. 

The two tunnels are blast excavated, mostly in solid section. Loose material in the portal areas is excavated with the protection of a jetting shield. In the Staldbach portal zone, there is mainly loose material confined by boulders and boulders of sandy-gravel matrix that has variable water content. In the transition zone to bedrock there is a large sector of graphitic schist. 

The rocky section is in the Pennine stratigraphy, which is composed of calcareous micaschists with quartz lenses.

• 4,255 m double-barrel
• 2,000 control systems
• Adaptive lighting