West Seattle Tunnel

The West Seattle Tunnel is part of a regional sewer conveyance system located in Seattle Washington. The tunnel was constructed for the Waste Water Treatment Division of the King County Department Of Natural Resources, from June of 1995 through the first quarter of 1997. The Geologic setting for this soft-ground tunnel consists of glacial, interglacial, glacio-lacustrine, and alluvial soils. This paper, prepared jointly by the owner and con-tractor, will describe project-related site geology, engineering considerations, construction, and dispute resolution/avoidance practices.