Experimental Study on High-pressure Air Cannon Impact Rock Breaking and Preliminary Site Application

To address rock excavation challenges in environmentally sensitive areas, this research team developed an innovative high-pressure air cannon integrated drilling and blasting machine. The technology combines energy-powered pneumatic impact principles with aerodynamic pulse technology, demonstrating effectiveness through comprehensive validation including concrete fragmentation trials at test sites and practical rock-breaking applications in open-cut tunnel foundation projects. Through modular integration of drilling, borehole sealing, and high-pressure pulse rock fragmentation capabilities, this equipment enables fully automated operation throughout the entire process. It offers significant advantages including explosive-free operation, minimal vibration and noise, and no toxic emissions, making it particularly suitable for applications with stringent safety and environmental requirements such as urban construction projects, tunnel engineering, and heritage conservation zones. Experimental results demonstrate that, with optimized parameters, including a 0.8 m free-surface distance and 30 MPa decompression pressure, horizontal borehole blasting achieved an energy efficiency of 2.125~2.345 kg/m(TNT equivalent) while generating interconnected fracture networks. In contrast, vertical borehole blasting produced asymmetric fracture patterns due to gravitational effects and stress redistribution, although single-cycle detonation successfully achieved decimeter-scale rock separation along predetermined stress-relief pathways. The study confirms the technical feasibility of high-pressure air-cannon rock fragmentation, while noting that its performance under complex geological conditions(including groundwater and fault zones) requires further research. Future directions include developing intelligent sensing systems for parameter optimization, investigating synergistic effects between impacts and energy-enhancing agents, and extending applications to subway shield tunneling and highway slope engineering, and ultimately advancing the widespread implementation of eco-friendly intelligent excavation technologies.