Comparative study of dynamic response of earth dam

Abstract

Full-scale experimentally determined dynamic characteristics of an earth dam determined from imposed dynamic forces are compared with those estimated from earthquake responses. The measured frequencies and modes of upstream-downstream vibrations are compared with those predicted by an existing two-dimensional shear-beam model. Shear strains and shear moduli were estimated from the full-scale tests and were plotted along with those estimated from the earthquake response analysis. The same procedure was followed for damping versus shear strain at different levels. Then the combined results were interpolated and extrapolated. The dynamic properties of the dam’s constituent materials estimated from low-strain full-scale tests are consistent with those determined from relatively large strains induced by the two earthquakes. Also the tests revealed substantial change in the dynamic properties of the dam; the behavior is typical of a yielding dynamic system