Study on the Mechanism of Ring-Shaped Dual-Energy Charging Blasting for Rock Fracturing

To investigate the energy-focusing effect of circumferential slotted tubes during blasting, a single/dual energy-focusing circumferential slotted tube blasting model was constructed using the coupled Smooth Particle Hydrodynamics-Finite Element Method (SPH-FEM) algorithm in ABAQUS numerical simulation software. The study focused on comparing the energy release mechanisms and fracture patterns of single/dual energy-focusing circumferential slotted tubes, with model blasting tests used to validate the simulation results. Numerical simulation results indicate: Single-energy-focus annular slotted tubes significantly control detonation particle flow direction, enabling directional energy release. Stress at the slotted section is approximately 7.5% higher than at non-slotted sections. Compared to single-energy-focus tubes, dual-energy-focus tubes exhibit an 8.5% reduction in stress at the slotted section. while the peak velocity of detonation particles ejected along the slit increased by approximately 15.9%. The deviation angle of the slit decreased by about 35.5%, resulting in more concentrated distribution of detonation particles along the slit direction and higher energy density. The stress and deformation of the outer slit tube were also better controlled, demonstrating superior focusing effects compared to the single-slit tube. Test results indicate that circumferential shaped charge blasting can form continuous circumferential cracks at the base of the blast hole, which initiate earlier than radial cracks and exhibit higher peak propagation velocities, demonstrating a distinct circumferential shaping effect. Compared to single-focus annular blasting, double-focus annular blasting increased the peak propagation velocity of annular cracks by 28%. The resulting annular crack propagation paths were smoother and flatter, yielding superior fracture initiation. Additionally, experiments revealed significant variations in annular focusing effects across different slit positions.