What's Blocking Seattle's Tunnel-Boring Behemoth?

Is it a giant rock? What about a sunken ship? Beneath Seattle's waterfront, a mysterious object has halted Bertha, the world's largest tunnel-boring machine. Stumped engineers are unclear on how long a highway tunneling project will be suspended.

1 minute read

December 20, 2013, 10:00 AM PST

By Jonathan Nettler @nettsj


Seattle Tunnel Boring

Ben Brooks / flickr

"Something unknown, engineers say — and all the more intriguing to many residents for being unknown — has blocked the progress of the biggest-diameter tunnel-boring machine in use on the planet, a high-tech, largely automated wonder called Bertha," reports Kirk Johnson. "At five stories high with a crew of 20, the cigar-shaped behemoth was grinding away underground on a two-mile-long, $3.1 billion highway tunnel under the city’s waterfront on Dec. 6 when it encountered something in its path that managers still simply refer to as 'the object.'"

Among the guesses offered by engineers, historians and visitors to a museum for the tunnel project include: a buried train engine, a giant boulder, a famous shipwreck, and Prohibition era "Bootlegger stuff".

"[Chris Dixon, the project manager at Seattle Tunnel Partners, the construction contractor] said that efforts to drain water and reduce pressure at the drill head, with a series of bore holes pushed down in recent days, could allow workers to get safe access to the blocked site as early as Friday." 

Thursday, December 19, 2013 in The New York Times

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I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching.

Mary G., Urban Planner

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