Jan. 14 Bertha Update: Going Hyperbaric – Source: WSDOT This press release by WSDOT is fascinating, you should definitely check it out. It describes the hyperbaric intervention that deep see divers performed to try and determine what has impeded the progress of the Bertha TBM on the Alaska Way Viaduct Tunnel project. They describe how a bentonite mud is injected in front of the cutterhead to create a "membrane" so they could pump air into the excavation chamber to create an air bubble that the hyperbaric divers could work in. The air pushes the bentonite membrane into the soil face and holds back the soil and water. They use the screw conveyor to remove sufficient material from the excavation chamber so that the divers can work in the top half of the excavation chamber.
Jan. 21 Bertha Update: Initial Results of Hyperbaric Inspections – Source: WSDOT In this press release, WSDOT reported that as of January 21, STP divers had spent more than 35 hours under hyperbaric conditions inspecting the TBM cutterhead from inside the excavation chamber. They removed a piece of bent well casing, pieces of PVC pipe, and found a large boulder or piece of concrete in a cutterhead opening.
Jan. 23 Bertha Update: More Hyperbaric Work, No New Findings – Source: WSDOT In this press release, WSDOT mainly just updated the total tally of hours worked by the deep see divers in the TBM intervention at the cutterhead. As of January 23, they were up to 68 hours of work performed during 17 sessions.
Jan. 31 Bertha Update: Further evaluation required before tunneling can resume – Source: WSDOT Bertha moved forward about 2 feet on January 28 to test the cutterhead and build the next tunnel liner ring. STP crews observed abnormally high temperatures in some components, similar to what was observed during the original stoppage on December 6. The made adjustments, moved forward another 2 feet but the temperatures persisted. The analysis will continue.
An article about DBM Contractors of Federal Way, Washington. They are a specialty geotechnical contractor and are working on the Capital Hill Station for the Sound Transit light rail system in the Seattle Metro area. […]
The WSDOT announced recently that the Seattle Tunnel Partners Joint Venture has requested a total of $188 million in change orders so far, and that the Department has denied $157 million of those, with $31 […]
A stretch of tunnel on Eastbound I-70 in scenic Glenwood Canyon Colorado was closed last March because of a 70-foot long crack in the ceiling. Since then the two-lane westbound bore has been handling both eastbound and westbound traffic while repairs to the damaged segment were undertaken. This project has a little of everything: heavy excavation, rockfall, slab reinforcing, geofoam, and even geogrid! Read on for more details, a map and photos. (Photo by Concrete Works Of Colorado)