RESPONSE OF DAMS TO EARTHQUAKES INCLUDING EFFECTS OF SEDIMENTS

Using a technique based on the boundary element method, results are obtained for two-dimensional dam-water-sediments-foundation systems subjected to ground motion. Both deep-stratum and half-space idealizations of the foundation are considered. The results confirm the findings of previous investigations with respect to dam-water and dam-foundation interactions. However, they are in contrast with some of the results of an earlier study obtained using the so-called "wave reflection coefficient" approach when considering dam-water-foundation systems. Specifically, in the case of a half-space foundation and a full reservoir, the "wave reflection coefficient" approach leads to substantial underestimation (approximately 24% for the system considered) of the peak value of the crest horizontal acceleration due to time-harmonic horizontal ground motion. Apparently, this is due to the excessive damping introduced into the dam-water-foundation system by the absorbing boundary condition imposed on the bottom of the reservoir in the "wave reflection coefficient" approach. © ASCE.