The analysis of damage mechanisms and vibration effects caused by cut blasting under various void shapes

Abstract

The effect of the void shape on cut blasting is investigated by establishing a damage analysis model for a void using an improved calculation formula for stress on the wall of the void. Additionally, an optimization scheme is provided for the “square void cutting theoretical model.” The vibration effect of the rock mass outside the excavation area is simultaneously monitored, and its validity is substantiated through experimental and simulation-based verification. The findings indicate that the variation of q2sinθ over time aligns with the dynamic loading process of wall stress in holes. Under the influence of longitudinal waves, thin-walled circular damage occurs, and tensile effects from reflected waves are influenced by impedance. In a square void cutting model, two-stage stress waves cause tensile shear damage and inward collapse in the rock mass along hole walls. The explosive energy generated by square holes significantly contributes to fragmentation of rock masses. The circular empty-hole cutting model generates significant vibrations in central areas due to resistance. Vibration velocity in 45° direction for circular holes is lower than that for square voids outside cuts while vibration velocity remains equivalent between circular and square holes at 90° direction.

Keywords

• Damage mechanism
• longitudinal wave impact testing
• dynamic evolution of stress
• numerical simulation of rocks
• vibration influence