The seismic analysis of dams constitutes a particularly difficult engineering task. Complicated dynamic phenomena such as fluid-structure and soil-structure interaction take place in this problem affecting the response of the dams. Such phenomena can be proved destructive for the dam body, and consequently a catastrophic threat for the downstream communities. This study attempts to analyse the dynamic behaviour of earth dam including the dam-foundation-reservoir interaction effects. In view of this development, Finite Element Method (FEM) models are developed, with the focus to be on their nonlinear response. A parametric study is carried out in regards to the geometrical parameters of a heterogeneous earth dam formed by sandy soil shells and impervious material core. Finally, the numerical models are subjected to 4 well-known ground motions and the resultant response is presented herein. A comparative analysis between a linear and a nonlinear model points out the similarities of their response for moderate intensity earthquakes. Nevertheless, this cannot be stated for higher intensities, as stiffness degradation effects take place.
Introduction