Fig. 1
From: Gotthard-Durchstich
Durchstich or Durchschlag: the breakdown of the final rock barrier in a tunnel project. The historical moment in the 57 km long Gotthard Base Tunnel, 15 October 2010, 2:17 pm—the face of the Tunnel Bore Machine appears, a large rock block falls, the audience is tense with excitement (photo adapted from Neue Zürcher Zeitung, 16 October 2010)