Abstract: The particle impact-assisted rock-breaking technology offers the advantages of high speed and efficiency, demonstrating effective rock-breaking capabilities on hard rock. In a recent study, the author investigated the influence of impact speed of single and double particles, the distance between double particles, and other factors on the surface, three-dimensional and sectional morphology characteristics of high-strength granite. This investigation involved a combination of particle impact testing and discrete element simulation. The study aimed to elucidate the impact parameters’ influence on the changes in impact crater depth, volume, and surface area. Additionally, it examined the distribution of rock-breaking cracks caused by particle impact and evaluated the effectiveness of hysterisis double-particle impact rock-breaking from the perspective of energy absorption rate. The results revealed a positive correlation between impact crater depth and impact velocity. Moreover, as the distance between particles increased, the impact crater underwent morphological changes, becoming separated, with a decrease in volume and an increase in surface area. The simulations indicated that the cracks primarily distributed at the grain boundaries of plagioclase and orthoclase feldspar, with the dominant failure mode being tensile failure. Furthermore, when employing a 5 mm-diameter steel particle on 200 MPa extremely hard granite, the energy absorption curve of hysterisis double-particle impact rock-breaking tended to flatten with increasing impact velocity. Notably, at a particle distance of 8–10 mm and an impact velocity of around 400 m/s, the optimal impact-assisted rock-breaking effect was achieved.

Key words: assisted rock breaking, particle hysterisis impact, impact parameters, damage characteristics of hard rock, energy absorption rate