Structural safety assessment of adjacent reinforced concrete beam structures subject to vibrations induced by controllable pneumatic impulse rock-breaking

Hard rock-breaking in complex and sensitive urban environments represents a critical technical challenge constraining urban development. This paper proposes a controlled pneumatic impulse rock-breaking technology and systematically evaluates its vibration impacts on adjacent structures through open-cut tunnel foundation pit experiments combined with reinforced concrete beam vibration monitoring. The results demonstrate: (1) The controlled pneumatic impulse rock-breaking exhibits a three-stage coupled interaction mechanism: impact stress wave-dominated initial fracturing, quasi-static pressure-driven crack propagation, and secondary fracturing induced by gas flow within fracture networks. This energy dissipation pathway shows distinct differences from traditional explosive impact rock-breaking. (2) Vibration attenuation demonstrates boundary condition dependency, with foundation beam zones conforming to exponential decay ( v max = 14.41 e −0.34 x ) and suspended beam zones following power-law decay ( v max = 25.63 x −0.569 ), necessitating vibration mitigation measures for suspended beams. (3) The predominant vibration frequencies concentrate in 10–50 Hz, overlapping with beam natural frequencies, creating resonance-sensitive zones at structure–geological coupling interfaces and far-field propagation termini. This research establishes a structure-vibration propagation parameter coupled analysis framework, specifically addressing quantitative characterization of blasting vibration attenuation patterns and low-frequency resonance risk prediction. The findings provide theoretical and technical support for safe rock excavation in sensitive urban environments, advancing vibration control technologies for underground space development.