Abstract
Seismic waves observed at dam site rock are not only necessary for seismic design of dams but are also important to research on the characteristics of seismic waves on hard bedrock. Many seismic wave measurements have been recorded at the base of embankment dams. The observed waves suffer the effects of dynamic interaction between the embankment dam and the foundation, and include the waves reflected through the dam body. In this paper, the effect of characteristics of frequency spectra of input waves and impedance ratio between dams and foundations on the response and dynamic interaction at the dam base was evaluated using FEM analyses. The observed seismic waves and microtremor measurements at dam sites verified the results of the FEM analyses. Next, an incident seismic wave on the basement layer was estimated analytically by excluding dynamic interaction from the observation at a dam base. The estimation was performed using the acceleration wave measured at the base of a rockfill dam during the Kobe Earthquake. The dam was located near the earthquake fault. The incident wave on the basement layer during the Kobe Earthquake was estimated by the proposed method.
