| The seismic performance evaluation of embankment dams are applied to confirm that the earthquake-induced settlement of embankment dams crest is enough small, because the overflow from the crest could cause catastrophic failure of embankment dams. Now in Japan, trial of “Guidelines for Seismic Performance Evaluation of Dams during Large Earthquakes (Draft)” has been conducted. According to the guidelines, earthquake-induced settlement of dam crest should be basically evaluated by the method combining dynamic analysis and Newmark’s method. This method uses the dynamic analysis based on the equivalent linearization method, and next calculates the deformation as an amount of displacement of the slip circle due to earthquake response. But other deformation evaluation method for embankment dams has been recently developed based on cumulative damage theory. The deformation evaluation method based on cumulative damage theory also uses the dynamic analysis based on the equivalent linearization method, and calculates the deformation as a residual strain by cyclic loading due to earthquake response.In this paper, we first describe dynamic analysis based on the equivalent linearization method for a rockfill dam with a central earth core, and then evaluate the settlement obtained from cumulative damage theory. The results of our research make it clear that the settlement of model dam crest ranges from about 36cm to 160cm based on cumulative damage theory due to an earthquake motion with a maximum acceleration of more than 700 gal. The observed settlement of the crest of existing embankment dams due to earthquakes are compared to the calculated values based on the cumulative damage theory, and we confirm that relationship between observed values of existing dams and calculated values of model dam has a good coincidence and that cumulative damage theory is available to evaluate the settlement of dam crest due to a large earthquake. |
