The Natomas East Main Drainage Canal (NEMDC) North Levee project entailed installation of a 1,500-foot-long by 3-foot-wide by 25-to-35-foot deep cement-bentonite slurry wall near Railroad Avenue in Sacramento as part of the American River Common Features project. The purpose of the slurry wall installation was to improve the levee flood protection rating to a 200-year storm event.
Work included the geotechnical design of a temporary bridge to span over a 12-inch diameter, high-pressure gas main to support heavy construction equipment. NV5 observed, logged, and sampled the 25- to 35-foot deep trench excavation to verify the wall bottom was embedded in a clay material. We also provided quality control sampling and testing during slurry production and placement. Testing of samples collected from the onsite batch plant and the trench included unconfined compressive strength, permeability, unit weight, viscosity, sand content, and filtrate loss.
During construction, NV5 performed laboratory and field testing of subgrade soil, aggregate base rock, and hot mix asphalt. Relative density testing was performed by sand cone and nuclear gauge methods. Storm water pollution control services also were provided by NV5.