Dynamic testing and analysis of embankment dams

A 62 m high earthfill and a 165 m high rockfill dam located in a Seismically active region in Turkey were tested by large vibration generators mounted on the crest. Natural frequencies and mode shapes for motion perpendicular to dam axis were observed. Shear strain amplitudes induced in the dam during testing were in the order of 10 percent and thus the properties determined pertain to the small-strain (linear) range of the dynamic stress-strain relation of embankment materials. The results of these tests were then combined with the available data from similar studies by others (1,4,8,9,11,15).with the following objectives: To develop an empirical expression for the small-strain fundamental period of embankment dams for a quick and reliable estimate of the period in preliminary earthquake response analyses, and To derive basic dynamic properties of embankment materials as a guide in selecting appropriate parameter values in more rigorous dynamic response analyses by shear wedge or finite element methods.