NEHRP Clearinghouse

Seismic Permanent Deformations in Earth Dams.
Lee, K. L.
National Science Foundation, Washington, D.C. Research Applied to National Needs., December 1974, 36 p.
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This report considers the problem of estimating the permanent deformations that are likely to occur as a result of an earthquake. The basic concept involves the assumption that seismic induced deformations are due to a softening of the soil by seismic shaking so that following the earthquake, the embankment will settle or deform to a new condition compatible with the new 'softened' stiffness of the soil. A method for estimating this softening effect from the results of cyclic laboratory tests is described as well as a method of formulating the analysis into a pseudo static type of finite element program. The relevance of this new type of analysis to actual problems is illustrated by analyzing 5 different dams which have been damaged by previous earthquakes. A fair agreement was found between the predicted and the observed deformations.
Ground motion; Earthquake engineering; Earth dams; Earthquakes; Finite element analysis; Earth movements; Soil mechanics; Embankments; Seismic waves