Statistical evaluation of the effect of size and strain rate on particle strength of rockfill materials

The deformation of rockfill materials is mostly caused by particle breakage and subsequent skeleton adjustment. To investigate the effect of size and strain rate on particle strength under seismic load, a series of single particle crushing tests with different sizes and loading rates were conducted. The results show that the particle strength increases with the loading rate, while the size effect on particle strength gradually weakens. Furthermore, within the framework of the weakest chain theory, the failure probability per unit volume and the spatial location distribution of microcracks are discussed, and a statistical model for quasi-static particle strength is established. The spatial location of microcracks follows a power law distribution, and there is a specific power exponent at different strain rates, so that the compound parameters of the particle volume and failure probability are gathered on a master curve determined by the weakest chain statistics. The strain rate effect reduces the failure probability per unit volume and makes the spatial location distribution of microcracks sparser.