Jobergtunnelen – the first use of NATM in Norway
The article describes the pre-construction and construction phase of the soil section of the Joberg tunnel, the first tunnel in Norway where the principles of the New Austrian Tunnelling Method were used on a planned basis. Brief account is given of the geological and geotechnical conditions at the site, extent of ground investigation and the technical solution of the tunnel as prepared by the designer. The risks and challenges of the design are described in more detail as seen by the contractor at the pre-construction phase of the project. The construction itself is then discussed giving comparison of the pre-construction view and the actual excavation progress. Some particular problems are highlighted and described in more detail. The economic and time aspects of the construction are also argued as to the feasibility of the future use of this method in other projects in Norway.