Research on the damage characteristics of rock masses based on double guide-hole blasting under high In-situ stress

Abstract

In complex high In-situ stress conditions, how to achieve ideal rock blasting effect by effective methods is often a difficult point in blasting operations. In this paper, we analyze the effect of guide holes on blasting effect by adding guide holes to the rock pre-treatment method, and carry out double-hole blasting experiments based on the blast point particle expansion method. The effect of blasthole spacing and ground stress on blasting effect is investigated at macroscopic crack effect, microscopic particle contact and stress response level. The study shows that: (i) The crack penetration effect can be enhanced by setting guide holes between blastholes, and the penetration effect is more obvious when the distance between blasthole and guide holes is less than 2.5 times the radius of the crushing zone. (ii) At the contact force chain level, when the distance between blasthole and guide hole is less than 2.0 times the radius of crushing zone, the pressure stress perpendicular to the direction of blasthole linkage inhibits the development of crack, and the pull stress parallel to the direction of blasthole linkage promotes the development of crack; at the contact number level, the distance between blasthole and guide hole The main force direction is perpendicular to the blasthole line direction when the contact number level is less than 2.0 times the radius of the crushing zone. (iii) With the increase of distance between blasthole and guide hole, the inhibition of crack by stress in the vertical direction is weakened, and the main force direction is parallel to the blasthole line direction.