Characteristics of Interfacial Waves Over a Liquefied Seabed and Their Effects on Sediment Suspension

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Abstract
Wave‐induced seabed liquefaction can enhance coastal sediment suspension, but the wave‐cycle‐scale influence of interfacial‐wave motion remains poorly understood. Wave‐flume experiments were conducted on a silty bed under two regular‐wave conditions to compare near‐bed hydrodynamics and sediment suspension between a non‐liquefied condition and a liquefied condition. Under the non‐liquefied condition, suspended sediment concentration (SSC) exhibited a double‐peaked intra‐wave pattern and generally varied with turbulent kinetic energy and Reynolds shear stress, suggesting predominantly shear‐related suspension. After liquefaction, sustained interfacial waves developed at the mudline, with a root‐mean‐square amplitude of approximately 1.4 cm. Around the onset of sustained interfacial‐wave motion, near‐bed SSC increased from approximately 1.3 to 2.6 g L −1 within 4–5 wave cycles, the intra‐wave SSC distribution shifted to a single‐peaked pattern, and its relationship with Reynolds shear stress weakened. During rapid mudline descent, upward turbulent sediment transport was strongest and accounted for approximately 93% of the positive cycle‐integrated turbulent sediment flux. Under the experimental conditions examined, these observations suggest that interfacial‐wave motion may provide an additional phase‐dependent mechanism modulating sediment suspension over a liquefied seabed, offering a physical basis for improving the representation of sediment transport over liquefied beds.
Funding Information
  • National Natural Science Foundation of China (42577185)
  • National Natural Science Foundation of China (42277138)

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