The San Pablo Reservoir is safeguarded by a 1919 earthen dam of hydraulically placed fill over alluvium. Modern seismic safety standards required upgrades to the dam. These upgrades included removal of the 140,000 cubic yard San Pablo Dam buttress, Cement Deep Soil Mixing (CDSM) of liquefiable sands, and reconstruction of a 300,000 cubic yard buttress. ENGEO served the contractor on this dam retrofit project and worked closely with the civil engineer, drilling and deep soil cement mixing subcontractors, East Bay Municipal Utility District, and the State Water Board during the construction of the dam upgrade.
ENGEO provided engineering geology consultation and coordination with the project civil and structural engineers to provide solutions to field issues; oversight for geologic logging of subsurface borings for inclinometer installation; and ongoing monitoring of the inclinometers and interpretation of data. ENGEO’s role also included the following: