Sinkhole Halts Seattle Tunnel Project

Tunnel boring machine will not be allowed to resume work until the contractor's analysis and work plans satisfy state experts

Engineering News-Record

Bertha, the large tunnel boring machine digging the new Seattle tunnel, was halted last week until contractors can determine what caused a large sinkhole to form over the area where the machine was operating. Bertha will not be allowed to resume work until the contractor's analysis and work plans satisfy state experts.

Contractor Seattle Tunnel Partners filled the 35-foot-long, 25-foot-wide and 15-foot-deep sinkhole with concrete.

Work was also halted earlier last week after a barge carrying soil began to tip and spilled some of its load into the water. Work was stopped to ensure worker safety and to prevent damage to the conveyor system.

(more on the work stoppage at the Seattle tunnel project...)

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