The town of Visp in southern Switzerland is located at a strategic pinch-point for traffic passing through the narrow Rhone valley. Here the A9 highway leads  through densely built-up residential and commercial areas. To increase the  inhabitants’ quality of life, the only option for a highway bypass was to go  underground. The main objective of the new highway is to enable a sustainable and future development, which links the whole Valais and brings real value to the population, industry and tourism.

 

 

Underground interchange connecting Valais to the Visp Valley

The Visp tunnel is part of an almost entirely underground bypass scheme and marks the final phase in the construction of highway A9 through the Valais area. This new tunnel is a complex underground structure, consisting of the north and south directional road tubes plus an underground interchange connecting Valais to the Visp Valley.

 

 

A diameter of 10.80 m makes the tunnel suitable for the use of a highway  tunnel.

The tunnel project started in 2014, and since then the northern tube (2645 m long) has been constructed following the completion of an exploratory tunnel in 2005. The southern tube mainly followed the existing smaller tunnel to the Visp valley, which was widened to a diameter of 10.80 m to make it suitable for use as a highway tunnel. Construction work also included crossings and the highway intersection.

 


350,000 m³ of rock have been excavated

Since the project’s start in 2014 more than 350,000 m³ of rock have been  excavated and, after crushing and grading, been used as fill material on several  of the A9 construction sites. Excavation of the Visp tunnel was completed in  2016, with the breakthrough of the north tube on August 22, 2016.

 

In close cooperation with the contractor, Sika was able to provide a  comprehensive package of solutions throughout the entire project. This comprised products for rock support plus various aspects of production and  placing for about 185,000 m3 of concrete and 150,000 m3 of shotcrete, as well as 150,000 m2 of membrane-based structural waterproofing systems for the tunnels.