INFLUENCE OF VISCOUS DAMPING IN THE DYNAMIC ANALYSIS OF AN EARTH DAM USING SIMPLE CONSTITUTIVE MODELS

The results of dynamic non-linear two-dimensional finite element analy ses of the Long Valley Dam in the Mammoth Lake area of California subj ected to a real measured earthquake are presented. A simple elastic-pe rfectly plastic constitutive soil mode is used to describe the stress- strain response of the soil and Rayleigh damping (i.e. viscous damping ) is applied to account for the lack of hysteretic damping. The effect of the initial stress condition and the Rayleigh damping ratio are di scussed, and the results of the analysis are compared to th measured r esponse of the dam and to results presented by previous researchers. G ood agreement is obtained in the up/downstream direction, but as exper ienced by previous researchers, the correct vertical frequency range i s not achieved. The limitations of using viscous damping combined with simple constitutive models when studying the dynamic behaviour of rea l earth dams ar shown. Copyright (C) Elsevier Science Ltd.