9320824 Bielak This project investigates the seismic performance of earth and rock-fill dams, focusing on the coupling effects between the dam and its support, as well as on the effects of the spatial variability of the incoming seismic waves. Current design methods generally assume a rigid dam foundation, whereas observations of the behavior of earth and rock-fill dams during earthquakes suggest that canyon-dam interaction can significantly influence their seismic response. The main objective is to elucidate the conditions under which dam- canyon interaction effects are practically significant, and to develop methods that can be used in design and remediation practice for calculating these interaction effects. The projects involves computer simulations with two- and three-dimensional models which reflect realistic conditions. In as much as the main focus is on gaining a clear understanding of the mechanism by which the dynamic coupling between the dam and the canyon affects the seismic response of the dam, attention is confined largely to dams constructed of either dry or dense saturated granular soils and cohesive soils that are not susceptible to liquefaction. Some consideration, however, is given to seismic liquefaction evaluation for cases in which loose saturated sands and cohesionless silts are present. ***
