Seattle Tunnel Partners and manufacturer Hitachi Zosen have begun testing components of the SR 99 tunneling machine as they prepare to resume mining. A few initial tests were performed last week, and several others are slated to occur in the coming weeks.This week’s highlights include tests of various pumps inside the machine, as well as the screw conveyor system that carries excavated material from the cutterhead to the back of the machine and out of the tunnel. All of the tests are being conducted by STP and Hitachi Zosen, who are jointly responsible for ensuring the machine is ready to complete the remainder of the tunnel drive. Future tests will include rotation of the machine’s cutterhead, which, according to STP, will occur in late November.Some reassembly work is ongoing. Major components of the machine are in place, but crews continue to weld pieces together and reconnect wires and hoses. STP’s most recent schedule shows that the machine will be ready to resume mining on Dec. 23. WSDOT cannot verify the contractor’s schedule. The narrated video below explains STP’s repair effort in more detail.Other workSTP crews have finished treating the ground north of the access pit. They began injecting grout into the soil there last month to stabilize the area where the machine will exit the access pit. Crews will soon place a thin layer of sand at the bottom of the pit; the rest of the pit will be filled after initial testing is complete.STP crews are also preparing to install glass walls at the operations buildings located at each portal. The north building’s glass will be installed first. Read more about those efforts in this post.— more —
Each month, Seattle Tunnel Partners submits an updated construction schedule to WSDOT. These schedules show STP’s latest projection for completing the project, in addition to listing a number of important construction activities they must complete along the way.STP’s latest schedule (pdf 291 kb), which was posted Thursday afternoon, shows that mining will resume on Dec. 23, 2015 – one month later than the date shown in the previous schedule. Accordingly, the tunnel opening date in the new schedule also has moved by one month, to April 2018. STP has told us the changes in the schedule reflect the current emphasis on giving crews the time they need to complete the tunneling machine repairs successfully.Like all large construction projects, the schedule for this project changes frequently. WSDOT cannot verify any of the dates shown in this schedule.Work continuesAs this Oct. 14 post explains, STP has begun treating the ground north of the access pit through a process known as jet grouting. This work will stabilize the ground above the tunnel as the machine exits the pit.Additionally, STP and manufacturer Hitachi Zosen are continuing to reconnect machine parts in preparation for mining. That work includes welding pieces together, and reconnecting hoses and wires. STP Project Manager Chris Dixon outlines the steps STP is taking to resume tunneling in this video (links to YouTube).— more —
As walls are installed at the north and south portal operations buildings in the coming weeks, drivers may be surprised by how little their view inside the buildings changes. The exterior walls of the large fan rooms will be made of glass, providing passersby with a glimpse of the everyday activities that will occur inside these important operation centers.
The decision to use glass walls arose out of the guiding principles for the operations buildings: to reflect their function and … more