Cyclic and post-cyclic monotonic behavior of crushed conglomerate rockfill material under dry and saturated conditions

The seismic behavior of two conglomerate rockfill materials used in two high rockfill dams, subjected to earthquake loads, has been studied. In order to evaluate the dynamic behavior, an extensive series of monotonic and cyclic tests were carried out on large cylindrical specimens of conglomerate rockfill materials using triaxial tests. This paper first studies the effects of drainage (dry, saturation) conditions on the mechanical behavior of conglomerate rockfills at two compaction levels, and grain size distribution subjected to monotonic loading. Loading frequency and drainage condition effects on specimen behavior have been studied under cyclic loads under both isotropic and anisotropic initial stress conditions. To study any sign of material degradation due to cyclic loading, the post-cyclic monotonic stress–strain curves were compared under “dry” and “saturated” conditions. Geotechnical parameters to be used in static and dynamic numerical analyses models have also been presented.