XU Ping1, 2, HOU Weiqi1, QIAO Shifan3, DONG Hui1, 2, LUO Xiaoguang1, 2, ZHAO Wei1
Journal of Vibration and Shock. 2025, 44(6): 144-156.
To investigate the propagation laws of energy waves generated by nearshore underwater borehole blasting and to evaluate the destructive effects of seismic waves and water shock waves on reservoir dam, as well as the damaging effects of seismic waves on reservoir shore pits, this study was conducted based on the underwater borehole blasting project at the water intake of the Second Water Source Project in Guilin City. Using a fully coupled Lagrangian-Eulerian algorithm, numerical simulations of nearshore underwater borehole blasting were carried out to analyze the changes in propagation patterns and attenuation laws of blasting energy waves, as well as the dynamic response characteristics of the reservoir dam and shore pits. The results indicated that: 1) The attenuation characteristics of the water shock wave peak pressure with the scaled distance charge (Q1/3/R), dam vibration velocity time history curve and the variation pattern of dam peak vibration velocity observed in field tests showed a high degree of consistency with the numerical simulation results. Both field tests and numerical simulations demonstrated that the attenuation characteristics of water shock wave peak pressure closely matched Cole's empirical formula, confirming the reliability of the numerical simulation model for underwater borehole blasting. 2) Based on an intuitive analysis of the propagation and attenuation characteristics of water shock waves in reservoir water and seismic waves in the reservoir bottom rock mass, the propagation process of blasting energy waves was divided into three stages: explosion stage, diffusion stage, and attenuation stage. The influence ranges of seismic waves and water shock waves caused by the propagation of energy waves, with a medium vibration velocity of v=0.1cm/s, were 270m and 206.28m, respectively, and both did not reach the foot of the reservoir dam. 3) The peak pressure of water shock waves significantly attenuated with increasing distance from the explosion center and depth. Based on the blast similarity analogy method, a dual-factor empirical calculation formula for water shock wave pressure, considering both explosion center distance and underwater depth, was established, which can be used to reliably predict the peak pressure of water shock waves at any position in the water area. 4) The propagation of blasting energy waves in the reservoir dam caused significant dynamic responses in the core wall and the dam body. The vibration response in the bottom region of the dam’s blast-facing side was intense, and localized damage occurred in the dam foot area. The peak vibration velocity at the monitoring point at the dam bottom reached 0.17cm/s, which is below the standard limit of 2.5cm/s, indicating that the dam was preliminarily in a safe and stable state; the maximum damage ratio at the dam foot was only 25%. To ensure the absolute safety of the dam, appropriate vibration isolation and protective measures should be considered. 5) The propagation of blast-induced seismic waves in the reservoir shore rock mass triggered sequential dynamic responses on the blast-facing side, bottom, side, and back-blast side of the pit. The peak stress and peak vibration velocity were highest at the top of the blast-facing side of the pit. Close-range high-charge blasting could adversely affect the safety and stability of the shore pit, necessitating strict reinforcement and vibration isolation measures in engineering practice. The findings can also provide a reference for analyzing the propagation laws of energy waves and assessing adverse impacts in similar engineering blasting projects.