A Study of the Seismic Response of Asphaltic Concrete Used as a Core in Rockfill Dams

Seismic response of the asphaltic concrete used as an impermeable core of a rockfill dam was investigated. In the first part of the study, geotechnical parameters of the asphaltic concrete were obtained from a series of monotonic and cyclic triaxial tests. In the second part, ۲D and ۳D Nonlinear numerical analyses were performed for the highest dam with asphalt concrete core in Iran (Shur River Dam) under seismic forces. Different stages of construction and reservoir filing were analysed using the hyperbolic model with finite difference method. Both ۲D and ۳D analysis confirms that the earthquake shock can lead to developing some cracks and increasing permeability of asphalt in the upper part of the core; moreover, maximum vertical deformations occur near the crest and at the lower part of the upstream slope. The pattern of the core deformation in ۲D analysis includes settlements of the shells behind the asphaltic core and the core remains upright, but ۳D analysis shows that the core can settle with the neighbouring shells. Furthermore, ۲D analysis shows more settlements in the shells and less crest accelerations in comparison with ۳D analysis. Shear strains in the asphaltic core have different trends in the two types of analyses.