The figures above show examples of 3-D models of three left rock wall “windows” exposed in three consecutive rounds. Each rock wall window was shotcreted at the next round, and therefore it was not visible starting from the next round. Therefore, these are virtual representations because the shotcrete covers the rock exposed in all preceding rounds, and leaves only the last round exposed. The gaps between adjacent rock “windows” are caused by the presence of shotcrete or muck at the base of the face.

These representations allow one to highlight relationships between fractures and fracture sets that otherwise would go unnoticed. For example, it is evident:

  • The lack of K1 (cyan color) in the second round.
  • The lack of K4 (orange color) at the end of each round. K4 only appears in the following round when the tunnel face is no longer vertical, but inclined and parallel to K4.
  • The lack of K3 (red) and K5 (purple) at the third round; this contrasts with the large presence of K5 in the second round.

These three rounds also make it clear how important it is to have proper lighting. In the first round, only the lights brought in by Tonon USA were used, whereas in the second and third round the contractor’s light was left on. Tonon USA lights are properly balanced and set to the proper temperature in order to reveal the actual color of the rock: a necessary condition to properly distinguish different rock types, and identify water seepage.

Here are two views of an entire rock cavern, which is 155 m (508 ft) long, 12.5 m (41 ft) wide, and 11 m (36 ft) high. The cavern was shotcreted once the face had advanced 30-50 m: the rock mass over the entire excavation is only visible on the computer! The value of such a 3-D documentation, which is permanently available, is invaluable.


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