Dynamic Response of Submarine Slope Under Continuous Internal Solitary Waves

Abstract

Internal solitary waves (ISWs) play a critical role in shaping submarine geological environments. The dynamic interactions between ISWs and seabed sediments can lead to complex fluid-soil responses, which are vital to understanding sediment transport, slope instability, and the formation of geomorphological features. In this study, a series of physical modeling tests were executed based on the typical characteristics of ISWs and sedimentary structure on continental slopes in the South China Sea. The results show that the velocity direction of the underlying fluid at the trough of the ISWs is opposite to the wave propagation direction. Based on internal Iribarren number Ir and nondimensional index BISW calculation results, the ISW breaking type in the tests is plunging breakers. The ISWs begins to break, when the ratio between the amplitude of the ISWs and the thickness of the underlying water is greater than 0.4. For every 0.05 increase in a/h2, the pore water pressure at T1, T2, and T3 increases by 30%, 30%, and 40%, and the earth pressure increases by 30%, 40%, and 30%, respectively. After the end of three consecutive ISWs, the surface earth pressure at the bottom, middle, and top of the slope decreased by 130%, 150%, and 180%, respectively. The θISW at different positions on the slope is in the range of 1.09-6.17 at different amplitudes, indicating sediment resuspension. These findings provide theoretical references for assessing submarine slope hazards, sediment transport pathways and marine infrastructure design in geohazard-prone areas.

Keywords: Continuous internal solitary waves, Seabed slope, Pore water pressure, Earth pressure, Dynamic response