Contractor Lane – a subsidiary of Webuild – has begun excavating the 4.3km-long storage tunnel with MudHoney, a 6.6m-diameter Herrenknecht EPB TBM which is mining from Ballard to Wallingford. The machine will line the tunnel with precast concrete segments.
Along the route there will be five shafts (at Ballard, East Ballard, Fremont, Queen Anne, and Wallingford) ranging in depth from 12m-24m to collect stormwater and sewage flows from each basin and convey them into the new tunnel.
The second machine, a 3m Herrenknecht slurry TBM, is mining a 2.4m-diameter conveyance tunnel from Fremont to Queen Anne that will pass under the Ship Canal and will connect Queen Anne’s wastewater basin to the larger storage tunnel being built by MudHoney. This tunnel, which will house a reinforced concrete pipe, is expected to take a little over three months to complete. The TBM was manufactured in 2014 and was refurbished following work on Seattle’s King County Fremont Siphon Project.
