GHD (formerly Winzler & Kelly) retained LACO to provide a geotechnical exploration for the proposed widening of approximately 1,950 lineal feet of South State Street in Ukiah, Mendocino County, California.
The project included widening of the existing roadway to accommodate a center two-way turn lane, bicycle lanes in each direction, a sidewalk on the west side, and bus turn-outs on both sides. Portions of the roadway are supported by up to approximately 8 feet of embankment fill above the surrounding terrain. The project design incorporated the placement of new embankment fill, culvert extensions, retaining walls, stormwater bioretention basins, and permeable pavements.
During the geotechnical exploration, our team utilized a series of geotechnical borings throughout the project area to characterize and sample subsurface soils. Results from the exploration and laboratory analysis were used to provide the design team with recommendations for subgrade preparation, fill placement, fill slope gradients, retaining wall design, and hydraulic loading rates (infiltration rates).