Cracking process and energy dissipation of sandstone under repetitive impact loading with different loading rates: From micro to macro scale

Abstract Rocks are widely used as building materials in many engineering applications. The repetitive impact loading can induce damage accumulation to rocks. To elucidate the multiscale damage and energy dissipation mechanism of sandstone under repetitive impact loading with different loading rates, dynamic compression tests were performed using Split Hopkinson pressure bar system (SHPB). In addition to the macroscopic deformation and energy absorption analysis, the optical microscope and the nuclear magnetic resonance technique were used to analyze the microstructural evolution of sandstone. A higher loading rate results in a larger number but smaller size of microcracks in sandstone sample, consequently, more macroscopic cracks and a higher energy absorption can be found in sandstone sample. In addition, despite the loading rate, the porosity shows a nearly linear relationship with the cumulative dissipated energy. The present results clarify the multi-scale damage evolution and energy dissipation of rock materials exposed to repetitive impact loading with different loading rates.