A correlation for permanent earthquake-induced deformation of earth embankments

Seismic design of earth dams and embankments is mainly controlled by the permanent deformation that may be induced directly or indirectly because of the design earthquake. Simple design charts, such as those developed by Yegian et al. [Yegian, M.K., Marciano, E.A., and Ghahraman, V.G. 1991. Earthquake-induced permanent deformations: Probabilistic approach. J. Geotech. Eng., 117, 35–50.], Hynes-Griffin and Franklin [Hynes-Griffin, M.E., and Franklin, A.G. 1984. Rationalizing the Seismic Coefficient Method. Miscellaneous Paper GL-84-13, US Army Corps of Engineers Waterways Experiment Station, Vicksburg, Mississippi.], Makdisi and Seed [Makdisi, F.I., and Seed, H.B. 1978. Simplified procedure for estimating dam and embankment earthquake-induced deformations. J. Geotech. Eng., 104, 849–867.], and Sarma [Sarma, S.K. 1975. Seismic stability of earth dams and embankments. Géotechnique, 25, 743–761.], are often used to obtain a preliminary estimate of the permanent, earthquake-induced deformation of earth dams and embankments. Comparison of permanent deformations estimated from these procedures with observations from 122 published case histories on performance of earth dams and embankments during past earthquakes indicate that the estimated permanent earthquake-induced deformations were, in general, smaller than the observed deformations. However, the observed permanent deformation, D_avg, was found to relate to the ratio of yield acceleration, a_y, and the peak horizontal ground acceleration, a_max. The scatter in the observational data, upon which the D_avg–a_y/a_max relationship is based, can be partly explained by the variations in the ratio of the fundamental (elastic) period of the earth structure, T_D, and the predominant period of the earthquake ground motion, T_p, and the magnitude of the earthquake, M_W.