The Brenner Base Tunnel will be 64 kilometers long and will be the centerpiece of the Scandinavian-Mediterranean TEN-T Corridor from Helsinki to Valetta (Malta). The tunnel comprises twin single-track rail tunnels with a service and drainage gallery in between.
The primary focus in this paper is on the construction of the 15km long exploratory tunnel Ahrental where a well-adapted TBM concept was used. Tunneling started from Ahrental (Austria) towards the Italian border in challenging terrain using a 7.93m-diameter Gripper hard rock TBM. The geology along the section was characterized as extremely challenging with quartz phyllite and shale and high overburden of up to 1300m. Numerous fault zones were predicted along the drive with expected loose to friable rock mass. The publication addresses in particular the special TBM design and project experiences with the operation of a Gripper TBM in challenging rock mass.