Research on the vibration reduction effect of water uncoupled charges in underwater drilling and blasting

In order to study the vibration reduction effect of water uncoupled charges in underwater blasting and reduce the harm to the protected objects such as adjacent buildings, theoretical derivation and field experiments are used to investigate the attenuation law of blasting vibration of water uncoupled charges. In theoretical derivation, based on Newton’s Third Law, the continuity condition of the medium, and the law of conservation of momentum of waves, the particle vibration velocity of the explosive shock wave after reflection and transmission between water and rock mass under two conditions of water uncoupled charge and coupled charge is derived by calculating the wave impedance ratio. The attenuation rate of the particle vibration velocity of the explosive shock wave transmitted into the rock mass under water uncoupled charge is obtained. The calculation results show that after the shock wave of the water uncoupled explosive is transmitted into the rock mass through the water body, the vibration velocity of the rock mass particles is only 3.8% of the vibration velocity of the explosive particles. Compared with the coupled charge, the vibration velocity of rock particles is reduced by 93.10%. The on-site experimental results show that by comprehensively adopting water uncoupled charge, hole by hole detonation, precise limitation of single hole charge and maximum charge for one detonation, and other shock absorption measures, based on measured blasting vibration data, dynamic adjustment of blasting parameters reduces the harm of blasting vibration and water shock waves to the protected object, ensuring blasting quality and engineering progress. Both theoretical derivation and field experiments have shown that water uncoupled charges have a significant vibration reduction effect in underwater blasting. The calculated attenuation rate of particle vibration velocity has theoretical guidance significance. The actual results obtain from field experiments provide practical experience and reference for vibration control in underwater blasting engineering, and form a set of construction technology for underwater drilling water uncoupled charge blasting.