Shear Moduli and Damping Factors of Earth Dam

In this study of an earth dam, a rational procedure is developed to estimate its dynamic soil properties, such as the shear moduli and damping factors, from its measured response to real earthquakes; the measured response includes strong-motion records from the crest and the base of the dam. The procedure permits study of nonlinear behavior by using the variation of stiffness and damping properties with strain levels. The Santa Felicia Dam, located in Southern California, was chosen for the analysis because it had been subjected to strong shaking during two earthquakes (with M_L=6.3 and 4.7), and was equipped with strong-motion instruments that yielded data on the structural response as well as the input ground motion at the site. The investigation is limited to the upstream-downstream response since existing analytical techniques for earth dams are restricted to horizontal shear deformation in that direction.