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.

To study the damage law of calcareous conglomerate under blasting, firstly, the damage fracture process and mechanism of calcareous conglomerate under blasting load were revealed based on the theory of damage fracture mechanics. A meso-scale model of conglomerate, including filler, conglomerate and interfacial transition zone (ITZ), was established by using LS-DYNA and Fortran programming, and the propagation law of explosive stress wave and its damage characteristics were analyzed. The damage fracture process of calcareous conglomerate under blasting can be divided into four stages, namely: compression damage in both gravel and fill; tensile damage in gravel and compression damage in fill; tensile damage in both gravel and fill; and tensile damage at the intersection of gravel and fill. Numerical results show that under blasting loads, the gravel has higher equivalent stresses, the fill has the lowest, stress concentration is evident at the ITZ, and the stress gap between the gravel and the fill decreases as the distance increases. The conglomerate sustains relatively minor damage, with a notable phenomenon of damage occurring around it. However, the filler experiences significant damage. The expansion of blasting crack in calcareous conglomerate forms mainly along the direction of stress wave propagation. Cracks tend to develop along the filler with lower physical and mechanical properties, as well as along the junction surfaces. The damage to the gravel is comparatively less severe. Blasting blockiness is mainly manifested as the filler wrapping gravel, and the distribution of blasting blockiness is affected by the bonding force at the intersection surface and the distribution of gravel.