Seattle Tunnel Partners lowering groundwater near the access pit

Posted on Oct 10 2014 2:20 PM

Seattle Tunnel Partners continues to prepare for excavation of the circular pit (pdf 2.5 Mb) crews will use to access and repair Bertha, the SR 99 tunneling machine. Crews are installing wells to lower groundwater in enclosed areas near the machine. This will make it easier to excavate the access pit and move the tunneling machine into the pit later this fall. 

Here are some shots of the site (taken by our time-lapse cameras), which is located to the west of the Alaskan Way Viaduct between South Jackson and South Main streets. The blue machine in the image on the right is installing one of the wells.
Access pit south   Access pit wells
Other significant work is also ongoing, including:
Crane assembly
Two new red cranes are now assembled near the site of the access pit. These cranes will be used to assemble the 2,000-ton modular lift tower that will lift pieces of Bertha from the pit.
Cranes at access pit   Crane assembly
Preparing machine parts 
In the coming weeks, new and replacement parts for the tunneling machine will continue to arrive from the manufacturing facility in Japan. Many of these pieces are being stored at a warehouse in Seattle until it’s time to install them in the machine. Below is a shot of the outer seal ring being manufactured in Japan earlier this year.


Outer seal ring

Highway construction in the tunnel
Crews have begun building the structures that will support the roadway inside the tunnel. STP plans to build approximately 450 feet of the structures before tunneling resumes.
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