Characterization of Young Bay Mud at the Port of San Francisco

San Francisco's Embarcadero Seawall was constructed between 1879 and 1916 by dredging an approximately 100-foot-wide and 30-foot-deep trench through native Young Bay Mud (YBM), and filling it with rock to create a pyramid-shaped dike up to 40 feet tall. Today the Seawall provides flood and wave protection to Downtown San Francisco and stabilizes hundreds of acres of filled land. Characterization of YBM (a very soft to firm estuarine clay deposited since the end of the last glacial period) is important for evaluating the seismic vulnerability of the Seawall. Monotonic and cyclic loading behaviors are characterized from integration of site-specific in situ and laboratory test data, including cone penetration tests, field vane shear tests, suspension logging, and laboratory direct simple shear tests. The site investigation is described and results from in situ and laboratory tests are presented. These data can be especially useful for reliable assessment of YBM behaviors at the bay margins and evaluation of YBM slope instability.