Seattle Tunnel Partners progress update: Construction of the access pit’s underground walls wraps up, preparation for dewatering begins
As we head into the last long weekend of the summer, we thought it was time for an update on Seattle Tunnel Partners’ progress to build the circular pit (pdf 2.5 Mb) that crews will use to access and repair the SR 99 tunneling machine.
The last time we updated you, STP announced that crews would continue to install the underground walls of the access pit through August. STP has notified WSDOT that there is one pile left to install before the circular pit is completed; they expect to finish it by the end of the week. Additional piles will be installed near the pit as part of the support system for the modular lift tower - the large crane that will hoist the machine’s 2,000-ton cutterhead and drive unit out of the ground.
Next up, dewatering wells. STP has notified us that crews will install several dewatering wells both inside the access pit and inside the enclosed area south of the access pit around the tunneling machine. Prep work is beginning now and crews should have them installed by mid-September. These wells will lower the groundwater inside the enclosed areas to make it easier to move the tunneling machine into the access pit, as well as to excavate the pit.
STP has notified us that tunneling machine operators will start Bertha in order to check internal systems in preparation for mining into the circular pit. Also, pieces of the three cranes that will be used to lift tunneling machine pieces out of the access pit are continuing to arrive from around the world. Soon you will see these pieces being assembled next to the access pit.
- NEW Video: View an animation of repairs narrated by STP Project Manager Chris Dixon (view on YouTube or download WMV file)
- Seattle Tunnel Partners repair work plan (pdf 4.8 Mb)
- Graphics showing access pit construction (pdf 2.5 Mb)
- Time-lapse camera of repairs
- Video of crews building the access pit (view on YouTube or download WMV file)
- Video of crews reconfiguring the tunnel launch pit (view on YouTube of download WMV file)
- Brochure of STP's repair plan (pdf 1 Mb)