Study on Dynamic Mechanical Properties and Microscopic Damage Mechanisms of Granite after Dynamic Triaxial Compression and Thermal Treatment

Abstract

As underground mining progresses deeper, ore bodies are situated under increasingly complex conditions, and geological disasters occur more frequently. Rock masses are prone to damage of varying degrees and types, making it challenging to use intact rock as a reference in practical applications. To investigate the dynamic mechanical properties of damaged rocks under realistic conditions, this study subjected granite samples to impact and high-temperature damage. We closely examined the changes in surface morphology and microstructure before and after damage. The study employed open porosity and a wave speed-based damage factor as indicators to explore the patterns of damage variation. Subsequently, uniaxial compression tests at different loading rates were conducted on the damaged samples to delineate the relationships between dynamic strength, damage, and loading rate. By calculating the sensitivity to loading rate effects, it was found that as damage increases, the rate effect gradually weakens. Moreover, changes in the post-peak segment of the stress-strain curves and grain size analysis further summarized the influence of damage and loading rate on the macroscopic failure characteristics of the specimens. This research provides valuable insights for the safe construction and stability assessment of deep mine rock engineering and also offers significant implications for the feasibility of non-explosive mining of damaged rocks.

Keywords: Damage, Dynamic Mechanical Behavior, SHPB, Microcrack Propagation