Vibration velocity and frequency of underwater short-hole blasting

Based on the measuring data of underwater blasting vibration and theregression analysis results of these data, two formulae usually used of blasting vibration velocitywere compared. Factors that can affect blasting vibration and frequency were summarized andanalyzed. It is thought that the effect of the number of freedom face and burden direction onblasting vibration should be considered during blasting design. Based on the relevant researchresults and the regression results of these data, a formula to calculate under water blastingfrequency was put forward.

Monitoring and Prediction of the Vibration Intensity of Seismic Waves Induced in Underwater Rock by Underwater Drilling and Blasting

All underwater drilling and blasting operations generate seismic waves.However,due to a lack of suitable vibration sensing instruments,most studies on the propagation of seismic waves have been limited to shorelines near construction areas or wharfs,whereas comparatively few studies have beerconducted on the larger seafloor itself.To address this gap,a seafloor vibration sensor system was developed and applied in this study that consists of an autonomous acquisition storage terminal,soft-ware platform,and hole-plugging device that was designed to record the blasting vibration intensities received through submarine rocks at a given measurement point.Additionally,dimensional analyses were used to derive a predictive equation for the strength of blast vibrations that considered the in fluence of the water depth.By combining reliable vibration data obtained using the sensor system in submarine rock and the developed predictive equation,it was determined that the water depth was ar important factor influencing the measured vibration strength.The results using the newly derivedequation were compared to those determined using the Sadowski equation,which is commonly used on land,and it was found that predictions using the derived equation were closer to the experimental values with an average error of less than 10%,representing a significant improvement.Based on these results the developed sensor system and preliminary theoretical basis was deemed suitable for studying the propagation behavior of submarine seismic waves generated by underwater drilling and blasting operations.

Analysis of fracture mechanism for surrounding rock hole based on water-filled blasting

The principles of fracture development during underwater blasting are examined based on explosion and impact dynamics,fluid dynamics,fracture dynamics,and field testing.The research reveals that the fracturing of the surrounding rock during underwater blasting is due to the combined action of shock and stress waves for the initial rock breakage and subsequent water expansion.The fracture development model for the surrounding rock of a drilling hole during underwater blasting is established.The rock fracturing range under the combined action of shock and stress waves is developed,as well as the fracture propagation rules after the wedging of the water medium into the fractures.Finally,the results of deep-hole underwater blasting tests on large rocks confirm the efficient utilization of explosive in the hole to improve the safety conditions.Accordingly,safe and static rock breaking under the detonation of high-effect explosive can be achieved.In addition,super-dynamic loading from the explosions and static loading from the water medium in the hole can be adequately combined for rock breaking.