An Experimental Investigation of the Effect of Interfacial Waves on the Evolution of Sliding Zones in a Liquefied Seabed

The sliding process of liquefied submarine landslides is generally regarded as being induced by the coupling of excess pore pressure accumulation and shear stress under surface wave action. However, the significant role of interfacial waves formed over the seabed surface upon liquefaction has been largely ignored. The characteristics of interfacial waves and their effect on the development of a seabed sliding zone are poorly understood. Wave flume experiments were conducted to observe the occurrence and evolution of the interfacial wave and sliding zone, combined with image analysis to extract interfacial wave parameters. The results show that the shear action of interfacial waves can cause progressive liquefaction sliding of the seabed and the formation of a sliding zone. The specific location and thickness of the sliding zone are always dynamically changing during the liquefaction development process and are consistent with the liquefaction depth. The wave height of liquefaction interfacial waves increases with liquefaction depth, and the maximum ratio of interfacial wave height to surface wave height can reach 0.175, corresponding to a maximum longitudinal width ratio of the sliding zone of 0.25. The continuously developing interfacial waves transfer the energy of surface waves to deeper areas, expanding the limit depth of sliding zone evolution. This study can provide theoretical guidance for the prevention and control of seabed instability and sliding disasters under extreme storm conditions.