Wave-seabed interaction is known to be a fundamental cause of sediment instability and entrainment. Observations of burial for surrogate munitions were made with a high frequency, sector scanning sonar acquiring acoustic images of the seabed every 12 min during a storm event in May 2013 in the northern Gulf of Mexico offshore of Panama City Beach, FL. Surrogate munitions burial depth was verified by divers. Driven by time series of pressure observed near the seabed, an existing poro-elastic wave-sediment interaction model in combination with a sediment failure criterion due to liquefaction (loss of vertical effective stress) was used to correctly estimate depth and timing of burial. We introduce the concept of liquefaction degree, which is defined as the portion of vertical effective stress at the sediment surface that is, counteracted by wave-induced pore pressures. The relationship between wave-induced pressure at the seabed and liquefaction degree is expressed by a complex transfer function, indicating the importance of the swell band with respect to infra-gravity and short-wave components. The liquefaction degree was used to construct and calibrate a dynamical relationship between wave action and acoustic backscatter observations near the seabed, taken as a surrogate for suspended sediment concentration. Predictions of backscatter based on liquefaction degree were accurate at time scales of 15 s–30 min during most of the time span analyzed and superior to predictions of backscatter based on shear stress. The observations and analysis provide evidence for the importance of wave-induced seepage forces in describing sediment liquefaction and entrainment processes.

中文翻译：

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波浪诱导埋藏和沉积物夹带的观察和建模：液化程度的可能重要性

已知波浪-海底相互作用是沉积物不稳定和夹带的根本原因。2013 年 5 月在佛罗里达州巴拿马城海​​滩近海的墨西哥湾北部风暴事件期间，使用高频扇形扫描声纳每 12 分钟获取一次海床声学图像，对替代弹药的掩埋进行了观察。替代弹药的埋藏深度由潜水员核实。在海床附近观察到的压力时间序列的驱动下，现有的多孔弹性波浪-沉积物相互作用模型与由于液化（垂直有效应力损失）引起的沉积物破坏准则相结合，用于正确估计埋藏的深度和时间。我们引入液化度的概念，定义为沉积物表面垂直有效应力的部分，即，由波浪引起的孔隙压力抵消。海床波浪诱导压力与液化程度之间的关系由一个复杂的传递函数表示，表明膨胀带对于红外线和短波分量的重要性。液化度用于构建和校准海床附近波浪作用和声学反向散射观测之间的动力学关系，作为悬浮泥沙浓度的替代物。在分析的大部分时间跨度内，基于液化程度的反向散射预测在 15 秒至 30 分钟的时间尺度上是准确的，并且优于基于剪切应力的反向散射预测。观察和分析为波浪引起的渗流力在描述沉积物液化和夹带过程中的重要性提供了证据。