Experimental study of the association between sandstone size effect and strain rate effect

The association between sandstone size effect and strain rate effect were investigated experimentally with a split Hopkinson pressure bar (SHPB) system. The sandstone samples with Φ50 mm and different lengths were loaded under the constant ratio of punch velocity to sample length to study their size effects. Sandstone samples with constant length of 25 mm were taken as the reference to study their strain rate effects. Results indicate that, under the same velocity of the punch, strain rate of each sandstone sample is inversely proportional sample length; dynamic strength of sandstone increases with the strain rate and the length to diameter ratio (L/D), and presents a quadratic curvilinear relation with strain rate while presenting a cubic curvilinear relation with sample L/D; the reasonable L/D of $50 mm sandstone samples ranges from 0.5 to 0.8; that dissipated energy can present a fixed proportional relation with punch kinetic energy is unrelated to sample length.