Numerical Assessment of the Deformation of CFRD Dams During Earthquakes

Alejo Sfriso
Wednesday, October 1, 2008
First presented: 
The 12th International Conference of IACMAG, 2008
Published paper
Rock Mechanics

A numerical procedure for the preliminary estimation of the earthquake-induced settlement of concrete face rockfill dams is presented. The method is based on a simple constitutive model that accounts for the key features of the behavior of coarse grained materials that affect the response of CFRDs, namely pressure dependent elasticity and a peak friction angle dependent on both pressure and void ratio. The actual earthquake design record is replaced by a simple sinusoidal base acceleration having an equivalent effect on the dam. The numerical model uses isotropic hyperelasticity and isotropic hardening/softening plasticity combined with stress- dilatancy theory, and thus is applicable to geometries and materials where only monotonic plasticity is expected to occur, as is the case of CFRD dams. A case study is presented where the procedure is applied to a CFRD 140 m high, located in Argentina and designed for a strong earthquake. The computed settlement compares well with an analytical estimation and with a decoupled numerical model of the same problem. The main advantage of the proposed procedure is that all material nonlinearities are accounted for by the constitutive equations, thus allowing for the usage of a simple mesh with no artificial sub-zonification.

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