Prediction of earthquake-induced permanent deformations for concrete-faced rockfill dams

Abstract

Prior studies highlight the importance of earthquake-induced permanent displacement for the safety assessment of the embankment dams. Concrete-faced rockfill dams (CFRDs) have become popular at especially seismically active regions with their high seismic energy absorption capacity. However, seriously damaged rockfill dams have been reported after some earthquake exposures. Even so researchers have focused on the dynamic response of embankments, few studies have been conducted to reveal the seismic behavior of rockfill dams. In this study, the issue under scrutiny is to establish a preliminary design procedure considering the earthquake-induced permanent displacement and acceleration response of CFRDs. For this purpose, numerical models are prepared with various geometric and material properties. Real earthquake records are used for seismic excitation. Dynamic analyses are conducted with a finite element method-based software. The equivalent linear analysis procedure is followed under two-dimensional plain-strain condition. Acceleration responses of dams are recorded at the centerline of the models. Then, the Newmark’s sliding block approach is utilized to calculate the permanent displacements from acceleration records. A procedure is developed for the engineers to foresee the likely permanent displacement at the preliminary design stage. To prove the reliability, the recommended procedure is applied to case histories, and then the results are compared.