Underground construction / geotechnics

The 1.2 km long twin tube Moutier Tunnel forms part of the A16 motorway, called Transjurane. This motorway connects the city of Biel to the French motorway network, crossing the mountainous Jura area. The tunnel crosses a geologically complex region with high tectonic stresses.

The tunnelling was mostly done using conventional mechanical machinery, i.e. rock splitters and hydraulic hammers. Safe support to the tunnel lining is provided by steel beams and sprayed concrete. In particularly difficult zones, tube shields were used and the cross-section had in some areas to be divided into 7 sub-sections for excavation.

The Gotthard Base Tunnel is the longest railway tunnel on earth. It is composed of two tunnels of 57 km length each. Within this mandate, detailed planning of the entire logistics for the installation of the railway technology was done.
Optimized processes and schedules had to be developed. The installation of the railway technology is carried out from two main and three smaller installation sites. These sites are equipped with a complex and highly efficient infrastructure to allow the railway technology installation process, which is unique in terms of scale and complexity, to be carried out according to very high quality requirements and a tight schedule.

The 1.5 km long twin-tube Büttenberg tunnel forms part of the new motorway bypass of the city of Biel in Switzerland. It provides increased traffic capacity, reduces travelling times on the motorway and greatly reduces traffic and congestions within the city of Biel.

The tunnels were built using a tunnel boring machine with an earth pressure shield. A particularity and special technical challenge was the fact that the tunnels cross a major railway line, used by 300 trains per day, with a vertical distance of only a few metres.