On the distinct element parameters used for earthquake ground motion simulation

To overcome the difficulties in the choice of parameters used for the distinct element method, some hints are presented with a main focus on earthquake ground motion simulation. As a natural period of vibration, especially the fundamental period is an important factor in any earthquake response, nature of the fundamental period of distinct element systems is closely investigated. Meanwhile, nature of the least period of vibration is also investigated because of its importance in the selection of time step of a direct integration scheme. Reduction in elastic wave velocity due to discontinuity is described on the basis of experimental measurement on aluminum blocks. In addition to analytical formulation on damping properties, accelerograms observed on a rockfill dam model are compared with simulated ones, giving a useful suggestion on the viscous damping.