Centrifuge modeling of underwater explosion near the water–soil interface

When an underwater explosion occurs near the seabed, the water–soil interface will have a significant effect on the bubble pulsation process, while the seabed dynamic response will also change. A series of centrifuge model tests of underwater explosions were designed and performed to investigate the blast effects near the water–soil interface. The influence of the water–soil interface on the bubble pulsation process was studied. The high-speed camera was installed to capture the bubble pulsation process, and the pore-water pressure sensors were used to record the pore-water pressure response of the soil. It was found that the interface slows down the bubble pulsation process, thereby extending the period of bubble pulsation. It also causes the bubble to expand in a non-spherical shape. Additionally, the pore-water pressure in the soil exhibits three distinct peaks, which are attributed to the shock wave, bubble expansion and bubble contraction, respectively. Compared to the peak pore-water pressure generated by the shock wave, the peak pressure caused by bubble pulsation is lower but persists for a longer duration, resulting in a greater impulse. When pipelines or structures are buried in the seabed, the bubble pulsation would cause more severe damage than the shock wave, becoming a predominant factor in damage that cannot be ignored.