Development of Predictive Equations for Earthquake Induced Settlement and Fragility Curves of Fill Dams

Abstract

Recently, as the incidence of earthquakes increases, it is necessary to secure the stability of dams, one of the major national facilities, against earthquakes. In case of fill dam, seismically induced settlement exceeding dam freeboard may lead to a dam failure. The prediction of settlement is important because it is also reported to be strongly related to longitudinal crack width and depth, which are critical indices used for safe evaluation of dams. The empirical correlation derived from numerical simulations is most often used. In this study, two - dimensional nonlinear dynamic analysis was performed to predict the behavior of CFRD and ECRD, one of the common types of fill dam. The accuracy of the numerical model is validated through comparison with a centrifuge test. A total of 20 recorded motions are used to account for the influence on ground motion intensity and magnitude. The calculated crest settlements are correlated to four ground motion parameters, which are peak ground acceleration (PGA), peak ground velocity (PGV), Aria Intensity (IA), and magnitude. It is demonstrated that using ground motion parameters in addition to PGA can significantly increase the prediction accuracy. Furthermore, the fragility curves for CFRD and ECRD are derived in this study for probabilistic damage estimation as a function of a ground motion intensity. The dam crest settlement, which is a widely used damage index, is used for minor, moderate, and extensive damage states. The settlement is calculated from nonlinear dynamic numerical simulations. The fragility curve is represented as a log normal distribution function and presented as a function of the peak ground acceleration.