Earthquake induced deformations on Earth-fill and rock-fill dams

Abstract

The fundamental criterion for stability analysis of an embankment dam is the factor of safety against sliding of a part of the dam slopes. Usually, the dam is treated as a safe structure if this factor of safety is greater than unity. In this case the dam body experiences elastic deformations only. But, if the dam is subjected to a strong earthquake motion its deformations far extend the elasticity limit, so permanent displacements take place. In such a case the factor of safety, as a stability criterion, becomes immaterial, and thus the character and magnitude of the permanent displacements become measures for estimating the overall stability of the dam as a structure. It is important too, that engineering judgement should be introduced in assessing the safety of any dam under consideration.

Having in mind all the above assumptions, an analytical procedure for estimation of permanent displacements has been developed, based upon the physical characteristics of the built-in material, as well as the nature of the ground motion and the response of the structure to that motion. Finally, the proposed procedure has been checked on a real case, where the Upper San Fernando Dam, damaged by the February 9, 1971 earthquake was taken as a pilot structure.