Influence of the water-skeleton interaction on the seismic response of earth dams

Abstract

This paper presents a numerical analysis of the influence of the water-skeleton interaction on the response of earth dams to seismic loading. The non associated Mohr-Coulomb criterion is used for the description of the behaviour of earth material. Analysis is first conducted under undrained condition; then a full coupled analysis is used for the investigation of the influence of the water-skeleton interaction on the seismic response of the dam. Comparison of the undrained, full coupled and drained analyses shows that the undrained analysis overestimates the natural frequency of the dam and consequently could lead to a miss estimation of its response. The full coupled analysis predicts an important attenuation in the dam response, which could result from the role of the water flow in the dissipation of the seismic energy in addition to the influence of the induced pore-water pressure excess on the reduction of the effective stresses in the dam. As a consequence, full coupled analyses are recommended for the seismic design of earth dams.