This 57-km tunnel under the Swiss Alps has nearly broken through after 11-years of work. This tunnel will create a ‘flat’ rail path through the Alps and become the world’s longest rail tunnel. [Source: World Tunnelling. Image: Alp Transit]
The 2-year process of excavating the 3,389 foot long fourth bore of CALTRANS’ Caldecott Tunnel is nearly complete. The tunnel is anticipated to be put into service in 2013 to help relieve a major traffic […]
WSDOT released an update on February 7 with some conclusions regarding the blockage that has stopped the Alaska Way Viaduct Tunnel Boring Machine, Bertha’s progress since December 6. Now they don’t think it was necessarily the well casing after all.
They cite two factors that contributed to the blockage. First, the cutterhead was clogged with material. You can see an cool short video of a worker unclogging the cutterhead. Not terribly dramatic, but still cool. The second factor was increased temperatures inside the equipment. STP discovered damage to a seal that protects the machine’s main bearing. They are still determining how the repairs will be done.
If you want to follow the chronology of this issue, read below for summaries and links to previous updates from WSDOT. And Check out the videos too! [Source: WSDOT]