Today crews on the Devil’s Slide bypass tunnels will break through after more than 3 years of excavation work. The pair of 4,000-ft long tunnels will each convey Highway 1 past a dangerous and landslide-prone stretch of California Coastline. The tunnels will open to traffic in early 2012. [Source: San Francisco Examiner. Image: San Francisco Examiner]
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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]