## 4 Results and Discussion  
Based on the fracture morphology of the concrete blocks, shock wave-strain responses, and electrical signal characteristics, a systematic analysis and discussion were conducted on the rock fragmentation effects of metallic wire explosions under different dielectric conditions. (1) Analysis of macroscopic cracks and fragmentation morphology. The fragmentation results revealed the fracture characteristics of concrete blocks after multiple electrical explosions. Overall, adding chemically active or high-conductivity dielectrics significantly increased the number, width, and penetration depth of the cracks. Dielectrics containing metallic particles (aluminum and iron powders) contributed to the formation of wider and more regular crack distributions, indicating that reductive particles may promote localized thermal energy release and accelerate the formation of main fracture channels. Oxide-based dielectrics (iron (III) oxide and copper (II) oxide) further enhanced crack quantity and penetration depth, accompanied by noticeable debris spalling. This suggests that oxidizing agents participated in thermochemical reactions, prolonging the effective duration and intensity of shock waves. High-conductivity solutions (sodium chloride and potassium chloride) exhibited slightly different crack patterns (Y-shaped and X-shaped distributions), demonstrating that increasing electrical conductivity can accelerate energy deposition, causing the shock waves to act more concentratedly on the medium. However, the CO\({}_{2}\)-dissolved liquid, despite increasing energy deposition, showed poor fracture performance. This indicates that the complex interactions of bubbles and pressure variations may offset part of the shock wave energy, hindering crack propagation. These findings illustrate that modifying the physical and chemical properties of dielectrics can regulate rock fragmentation morphology, enabling future applications in precision rock-breaking operations. (2) Analysis of shock wave-strain response and energy transfer characteristics. The strain waveforms demonstrated that all dielectric materials exhibited sustained oscillations and secondary shock waves following the primary shock wave. The amplitudes and durations of these oscillations varied significantly depending on the dielectric type. Oxide-based dielectrics and high-conductivity solutions were associated with stronger secondary shock waves and higher equivalent energy values. This indicates that extending the energy release process or accelerating energy deposition can enhance the persistence and intensity of the shock wave effects. For the CO\({}_{2}\)-dissolved liquid, the presence of gas bubbles resulted in significant contraction deformation observed in the later stages of the strain curves. This behavior can be attributed to the compressibility of the gas, which increased the deformation capacity of the concrete blocks. These findings highlight the complex influence of dielectric properties on energy transfer and strain response during the electrical explosion process. (3) Analysis of electrical signal characteristics and the discharge process. The voltage, current, and deposited power waveforms indicate that under fixed energy storage conditions, dielectrics with different mechanisms have minimal impact on the discharge mode but can significantly alter the discharge process. Oxide-based dielectrics delay the breakdown moment by absorbing energy, thereby prolonging the discharge duration. High-conductivity solutions accelerate energy release, as reflected in a steeper rise in deposited power and a shorter discharge time. For the CO\({}_{2}\)-dissolved liquid, the increased gas pressure suppresses the expansion of the discharge channel, resulting in an energy deposition efficiency of 60%, the best performance observed in this study.