Investigation of the Explosion Process of Liquid Oxygen Charges with Different Absorbents Based on High-Speed Imaging

Liquid oxygen (LOX) blasting is a novel gas-based rock fracturing technology that relies on rapid phase transition and volumetric expansion to generate high-pressure gas for rock breakage. To address the unclear mechanisms of LOX phase transition, the poorly understood expansion process, and the uncontrollable effects of absorbent materials, this study investigates the complete explosion process of LOX charges with various absorbents. An experimental setup was developed, and high-speed imaging was employed to track the explosion behavior of LOX charges using different absorbent materials. Video data were processed to analyze the ignition-to-detonation time and critical explosion stages. The results demonstrate that the structural and combustion characteristics of absorbents play a decisive role in the LOX explosion process. Fibrous absorbents, due to limited LOX retention and slow combustion rates, cause delayed ignition and post-blast secondary combustion. In contrast, granular absorbents—with higher specific surface areas—enable efficient LOX absorption and complete combustion, significantly reducing ignition time and leaving no residue. Regulating the microstructure of absorbents can effectively adjust the coupling among LOX fixation, combustion rate, and energy release. For the first time, high-speed imaging captured asymmetric charge displacement induced by the combined effect of absorbent combustion rate and charge structure, which is compared to punching phenomena observed in field-scale blasting. Future studies should focus on developing new absorbents with moderate combustion rates, strong LOX retention capacity, and low cost to enhance the safety, efficiency, and engineering applicability of LOX blasting.