Numerical simulation of surrounding rock damage induced by different explosive casings in slotted charge blasting

To investigate the influence of slotted charge casings made of different materials on surrounding rock damage, single-hole and double-hole numerical models were established using finite element software. The effects of five casing materials – Cuprum (Cu), Aluminum (Al), Polyvinyl Chloride (PVC), Acrylonitrile Butadiene Styrene (ABS), and Polymethyl Methacrylate (PMMA) – on rock damage were compared, with particular attention to the evolution of stress distribution, crack propagation, and directional energy transfer in the surrounding rock. The results show that in the single-hole model, Cu casings exhibit pronounced fracture directionality and strong crack connectivity along the slotting direction, whereas in the double-hole model, the interaction between boreholes further enhances fracture penetration. PVC demonstrates stable main-fracture orientation, while PMMA casings provide moderate energy transfer and effective control of damage in both single-hole and double-hole cases. These findings offer a theoretical reference for the optimized design of slotted explosive charges and material selection, and provide technical support for achieving efficient, low-damage rock blasting in engineering applications.