tunnel boring machine
The contractors building a tunnel under Seattle have invited the media to a special viewing of Bertha, the world’s largest tunnel boring machine, as they prepare to pull it out of a pit for repairs.
Washington state archaeologists who took a look at shell deposits found by crews digging a 120-foot-deep pit that will provide access to a stalled Seattle tunneling machine have given the all-clear signal for work to proceed.
Bertha, the broken-down tunneling machine, moved forward three feet during recent testing, while workers building an underground circular pit that will allow access to the machine finished installing the last of 84 large concrete cylinders known as piles.
The new tunnel would allow workers to dig up and repair the now-stuck boring machine
Bertha, the machine boring the State Route 99 tunnel in Seattle, will not resume digging until the end of March 2015 and that the tunnel will not open until November 2016, according to the Washington State Department of Transportation.
The Alaskan Way Viaduct has sunk nearly half-an-inch at one location where a machine has been boring a highway tunnel under downtown Seattle.
Seattle’s massive tunneling operation is on hold yet again due to ongoing problems with the world’s largest boring machine, officials said Friday.
The giant machine digging a highway tunnel under Seattle is expected to resume light work this week, but officials still don’t know what stopped the giant drill for nearly two months, the Washington State Transportation Department said late Monday.
Crews have found a hard object more than 3 feet wide lodged in the tunneling machine that’s currently stalled 60 feet under the city of Seattle, officials said Wednesday.
The state Department of Transportation said Friday the 8-inch-diameter pipe was discovered protruding through an opening in the machine’s cutter-head.