Photo of the day

From an In Focus post on caves and tunnels.  I love tunnel boring machines.  So cool.

The cutting head of “Bertha,” the massive tunnel boring machine currently stopped underground near downtown Seattle while waiting for repairs, at the bottom of a 120-foot access pit after a 270-ton section of the front shield was removed and lifted to the surface with a crane on March 19, 2015. The piece is the first of several big crane lifts that will be needed to bring the cutting head and other parts to the surface to complete repairs on the machine, which was digging a 1.7-mile highway tunnel as a replacement for the Alaskan Way Viaduct.

About Steve Greene
Professor of Political Science at NC State

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