Study on Attenuation Mechanism and Parameter Optimization of Blast-induced Seismic Waves in Underwater Drilling Blasting Via Gas-filled Vibration-reduction Holes

Underwater drilling and blasting are extensively employed in hydraulic engineering projects like waterway regulation, yet the induced seismic waves present substantial safety hazards to adjacent structures. This research introduces an integrated vibration mitigation strategy utilizing gas-cushioned shock-absorption boreholes for effective blast vibration control. The vibration attenuation mechanism was thoroughly examined through systematic analysis. Numerical simulations evaluated the vibration suppression performance across 9 distinct configurations of gas-filled shock-absorption holes with varying row and spacing arrangements, with comparative analysis against non-gas-filled conditions. Field test validation confirmed the practical efficacy of the gas-filled shock-absorption hole technology. The results demonstrate that shock-absorption holes modify the rock mass wave impedance distribution, generating discontinuous interfaces. Gas filling in these holes significantly improves wave reflection and attenuation. Numerical analysis identifies an optimal configuration with 0.6 m hole spacing and 1 m burden for maximum blast vibration reduction, and comparative data reveals 10%~28% higher peak particle velocities in non-gas-filled scenarios. Finally, the field verification confirms up to 40% seismic wave reduction using gas-filled shock-absorption holes. This study provides a reliable theoretical basis and practical reference for vibration control in underwater blasting.