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.
Golder was the geotechnical designer for two of the most challenging segments of the Stockholm City Line in Sweden. Their work included foundation improvements for a tunnel beneath a historic portion of Stockholm, 3D modeling […]
The GAP rail-trail is 150 miles of hiking and biking between Cumberland, Md, and Pittsburgh, Pa. created along the former railway line. In Cumberland, the GAP joins the C&O Canal Towpath, creating a continuous 335-mile long trail experience all the way to Washington, DC. It’s become a favorite biking destination for people from around the Mid-Atlantic states. One of its main tunnels, the Pinkerton Tunnel, an 849-foot former Western Maryland Railway tunnel, has been closed since 1975 due to erosion and unstable conditions. The Allegheny Trail Alliance, the organization that built and now maintains the 150-mile GAP, and the Somerset County Rails-to-Trails Association (SCRTA), wanted the tunnel reopened and helped fund the project.
[Editor] Click through for the rest of the press release from GeoPrac sponsor, NCFI Polyurethanes (makers of TerraThane). [/Editor]
Pittsburgh’s light rail expansion project dubbed the North Shore Connector Project has passed underneath the Allegheny River despite some earlier troubles. The cut and cover tunnel portion is complete, and the TBM bored portion of […]