Seattle Tunnel Partners released a new schedule this week for the repair of the damaged seals on the Bertha Tunnel Boring Machine. This revised schedule shows that the TBM won’t be digging again until March of 2015. The excavation of the pit to access the TBM will begin at the end of May, a delay caused by additional archaeological work. By October they hope to have the cutterhead removed to conduct the repairs, and the machine will undergo testing in February of 2015 with tunneling resuming in March of 2015. [Source: WSDOT. Image: WSDOT]
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Feb. 7 Bertha update: Two factors contributed to tunnel stoppage
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]