Tunnel hole-through

When the two sections of a tunnel under construction meet
Dismantling the tunnel boring machine 10 days after the hole-through on the Gotthard Base Tunnel in Switzerland.

Tunnel hole-through, also called breakthrough, is the time, during the construction of a tunnel built from both ends, when the ends meet,[1] and the accuracy of the survey work becomes evident. Many tunnels report breakthroughs with an error of only a few inches, for example:

  • the 1858 Blue Ridge Tunnel – 6 inches (150 mm)
  • the 1944 Blue Ridge Tunnel replacement – 4 feet (1.2 m) - 1944
  • the Lötschberg Base Tunnel – 10 cm[2]
  • the Holland Tunnel - 1 cm[3]

See also

  • Cascade Tunnel

References

  1. ^ "Governor Rockefeller and Mayor Lindsay Attend 'Holing Through' of 63d St. Tunnel". The New York Times. October 11, 1972. Retrieved January 24, 2017.
  2. ^ Lotschberg
  3. ^ "ASCE Metropolitan Section - Holland Tunnel". www.ascemetsection.org. Retrieved 2020-11-21.

External links

  • South Africa Gautrain tunnel breakthrough
  • Australia Brisbane Clem 7
  • Switzerland Gotthard tunnel
  • Switzerland Lotschberg - 10 cm


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