Dynamic response and damage mechanism of conglomerate under blasting loading

To investigate the mechanical response and damage characteristics of conglomerate under blasting conditions, a theoretical computational model for conglomerate blasting zoning was proposed, grounded in the principles of multi-media wave dynamics and tailored to the structural properties of conglomerate. A mesoscopic numerical model for conglomerate blasting was developed, incorporating the matrix, gravel, and their cementation interfaces. Dynamic impact tests on conglomerate specimens were conducted using an electromagnetic split Hopkinson pressure bar (SHPB) system to validate the accuracy of the numerical model material parameters. Subsequently, single-hole blasting simulations were performed on conglomerate with varying explosive types and blast hole diameters, and the area of the crushed zone and crack distribution were quantitatively characterized. The results show that the effective stress in gravel exceeds that in the matrix under blasting loading, and the matrix around gravel is more prone to damage. With the increase in blast hole diameter and explosive performance, both the area of the crushed zone and the fractal dimension of cracks increase. However, when using low-performance explosives, the growth rate of the crushed zone area slows down as the diameter of the blast hole increases, while the growth rate of the fractal dimension of cracks accelerates. These findings can provide reference for gravel blasting engineering.