Breakage behavior of gravel rock particles under impact force

To investigate the rock particle breakage behavior subject to impact load, a series of split Hopkinson pressure bar (SHPB) tests were conducted on selected Nishan rock and Shoushan rock particles within gravel size range at different strain rates. Both rock particles exhibit a typical strain softening macrobehavior and their dynamic peak strengths increase with strain rate. A dynamic increasing factor (DIF) is used to describe this strain rate effect. Based on the SHPB test, a constitutive model is proposed for the two types of rock particles to describe their dynamic stress–strain behavior considering strain rate effect and damaging effect. Grain size distribution of fractured rock particles was analyzed, which reflected the fragmentation characteristics quantitatively. A fractal theory was used to describe the fragmentation characteristics and dynamic strength of both types of rock particles. Dynamic strength was found to vary differently with fractal dimension for Nishan rock and Shoushan rock. ? 2021, OWZ.