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COMMISSION INTERNATIONALE DES GRANDS BARRAGES ------- VINGT-SIXIÈME CONGRÈS DES GRANDS BARRAGES Autriche, juillet 2018 ------- SEISMIC ASPECTS IN THE DESIGN OF EMBANKMENT AND ROCKFILL DAMS CAMILO MARULANDA Technical Manager, INGETEC COLOMBIA EXTENDED ABSTRACT Historically, embankment dams have usually performed well during earthquakes. However, earthquakes can undesirably affect embankment dams in different ways. One of the most obvious way is by causing instability or large deformations in the dam, due either to strong shaking, or to increases in pore pressure and resulting decreases in strength (caused by cyclic loading). One of the most well-known cases of liquefaction and instability of a dam during an earthquake, is the Lower San Fernando Dam, where a portion of the embankment liquefied during the 1971 San Fernando earthquake and slid, leaving only about 3 feet of freeboard remaining to contain the reservoir. Dams have also failed due to erosion through cracks caused by an earthquake. Consequently, earthquakes may induce instability in the slopes of the dam, differential settlements and cracks. The assessment of the behavior of an embankment dam under seismic loading typically includes the following aspects: 1. Identifying and characterizing potential sources of earthquake loading, whether known faults or historic seismicity not associated with known faults. 2. Determining the appropriate loadings to apply in the analyses. 3. Determining the properties of the embankment and foundation materials, 7