Abstract
Static finite element analyses and laboratory measurements suggest that the shear modulus of soil in earth dams and embankments increases approximately as the 2/3-power of the distance from the crest, a variation that is also confirmed from field measurements of shear wave velocities in actual earth and rockfill dams. A shear-beam model has been developed and is outlined in this paper that accounts for such an increase of modulus with depth. The main thrust of the paper is to evaluate this model by comparing its predictions with the recorded response of a number of dams and embank-ments subjected to earthquake or man-induced vibrations. It is demonstrated that the model successfully explains observed modal displacement shapes, peak accelerations and seismic coefficients experienced by several Japanese, one American and one European dam, as well as by a large-scale laboratory embankment model. Consequently, the model offers a significant improvement over the classical, homogeneous shear beam model that is presently used to evaluate the seismic safety of earth dams.
