90-0012 Two-Dimensional Two-Phase Elasto-Plastic Seismic Response of Earth Dams A.N. Yiagos (Supervised by J.Prevost) 1990 Princeton University 292 PB91-110197 0 In this report a simplified, efficient and cost-effective numerical procedure to perform the phenomenological elasto-plastic seismic response analysis of earth dams is developed. The procedure is applicable to long dams with nearly symmetrical triangular cross sections made of homogeneous horizontal layers, and accounts for the presence of water in the dam material. The method is based on a two-dimensional Galerkin formulation of the equations of motion for the dam material, and fully coupled soil skeleton and pore water equations are used in the saturated portion of the dam. The soil skeleton nonlinear hysteretic response is modeled using an effective stress multi-surface elasto-plastic constitutive model. The ability of the model to simulate the occurrence of liquefaction in a dam is also demonstrated. Finally, parametric studies are performed on a model of the Long Valley dam (Mono County, California) to illustrate the influence of the most important material parameters on the earthquake response. Santa Felicia Dam, Ventura County, California, Long Valley Dam, Mono County, California, Liquefaction, Earth Dams, Seismic Response, Elasto-Plastic Models, Soil Behavior, and Galerkin Formulations.