Examining the Seismic Behavior of Rock-Fill Dams Using DEM Simulations

High rock-fill dams are planned or under construction in high seismic intensity area, challenging the seismic design of those dams. This study aims to examine the seismic behavior of rock-fill dams using DEM simulations. The focus is put on the permanent deviatoric strain field and the shear stress-strain loops in rock-fills which can hardly be measured in the experiments. The acceleration response and crest settlement observed in the simulations are consistent with those monitored in centrifuge shaking table tests. The key feature of permanent deformation is surface sliding, and the size of the associated shear zone is influenced by the slope angle. Moreover, there also exist deeper shear zones with a relatively low level of shear strain compared with the surface sliding zone. The rock-fills near slope surface may experience a sharp increase in shear strain after several loading cycles, and the associated strain accounts for a large amount of the permanent shear strain. The variation rate of the shear strain can be decreased, and then the shear strain can hardly develop although the input motion is still strong, reflecting the effect of pre-shaking on the seismic behavior of dams. Moreover, the timing of sharp increase of shear strain is different for rock-fills at various locations, suggesting the complexity of the seismic behavior of rock-fill dams.