Investigation of Liquefaction Potential of Alluvium underneath an Earth Embankment Dam

Abstract

The Santa Clara Valley Water District (SCVWD) owns and operates the Calero Dam facilities, which include the Main and Auxiliary Dams. The Main Dam is about 98 feet high and straddles a former wide stream valley. A large part of the downstream embankment is underlain by coarse grained alluvium (CGA) that is potentially liquefiable during strong earthquake shaking. The liquefaction potential of the CGA was evaluated using SPT-based methods. Validating analyses with the Loma Prieta event suggest the SPT-based liquefaction evaluation methods satisfactorily explain the lack of liquefaction observation during the event. The influence of embankment overburden on the liquefaction potential of foundation alluvium was investigated as part of the study. The findings indicate that the presence of the embankment likely had only minor effects on the liquefaction resistance of the CGA.