Response of earth dams in semi-elliptical canyons to oblique SH waves
Dakoulas, Panos C.
Master of Science
Two analytical closed-form solutions are developed for steady-state lateral response of earth and rockfill dams built in semi-elliptical canyons. In the first model, the canyon is assumed to be rigid, while the dam is idealized as a two-dimensional linearly-hysteretic elastic body deforming only in shear (shear beam). Both free and base-induced oscillations are studied for various canyon geometries. In the second model, the canyon is assumed to consist of flexible elastic rock, subjected to asynchronous excitation consisting of obliquely incident harmonic SH waves. The solution accounts in a rigorous way for the complex wave reflection, transmission and diffraction phenomena associated with the dam-filled canyon. The study focuses on the effects of: (a) the angle of incidence, (b) the impedance ratio and (c) the canyon narrowness. It is shown that the effects of radiation damping and ground motion spatial variability are very important.