ABSTRACT
Exploration ahead of the tunnel face is extremely important in reducing geological and hydrogeological risk in tunnel excavation. In particular, direct investigations in deep-seated tunnels like the Brenner Base Tunnel are applied to verify in advance whether planning assumptions regarding the expected rock mass conditions and hydrogeology were correct. If these investigations are planned as part of a continuous Drill&Blast cycle, a sort of “macro” cycle is introduced, which includes a series of ordinary sub-cycles. In mechanized tunneling, due to the continuity of this type of excavation, exploration activities ahead of the face can be planned in parallel with other, more maintenance-oriented, activities, and therefore cause just short production interruptions. This paper examines the impacts of the direct investigation activities ahead of the tunnel face, which have so far been performed during the excavation of the BBT exploratory tunnel, on the production cycle.
