A buried steel pipe is mostly to blame for stopping the giant tunnel-boring machine Bertha, which has been stuck since Dec. 6 along the Seattle waterfront near South Main Street. The long pipe was an 8-inch diameter, 115-foot-long “well casing,” used to measure groundwater during studies in 2002 on the Alaskan Way Viaduct replacement project, project officials said. Matt Preedy, the deputy…More
Topic: highway 99 tunnel; bertha
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Workers at the Highway 99 tunnel project have begun drilling 12 vertical wells to pump away massive amounts of groundwater surrounding Bertha, the Highway 99 tunnel machine. If the operation succeeds, there will be less pressure immediately inside and outside the cutting face, simplfying efforts to clear a blockage in Bertha’s underground path. The machine has been stuck…More