Impacts of soil properties on bluff recession under combined waves and surge actions: An experimental study with uncertainty quantification

Soil mixtures with five fines contents, two water contents, and two relative densities underwent soil mechanics tests to quantify their strength indices. Then small-scale steep beaches and bluff models were built with those soil mixtures in a small wave flume and subjected to varying water levels and waves. The equilibrium beach profile of the model containing a higher fines content, higher relative density, and the optimum water content, followed a concave down profile, while that of the models with the lower density and/or lower fines content, was concave up. The bluffs composed of the materials with the optimum water content exhibited a reduced crest recession compared to those with the constituent materials dry of optimum. The recession rate of the bluff crest decreased with the increase of the effective cohesion. For a given effective cohesion, the recession rate was significantly influenced by the relative density. The impact of the effective cohesion on the recession rate for the bluff composed of the looser soil was significantly greater than that of the bluffs with the denser constituent material. Furthermore, uncertainties associated with the impacts of the variations in the fines content, relative density, and water content on the recession rate were quantified.

对具有五种细粒含量、两种含水量和两种相对密度的土壤混合物进行了土力学试验，以量化其强度指标。然后，在小型波浪水槽中用这些土壤混合物构建小型陡坡海滩和陡崖模型，并使其经受不同的水位和波浪作用。含有较高细粒含量、较高相对密度和最佳含水量的模型的平衡海滩剖面呈下凹形，而密度较低和/或细粒含量较低的模型的平衡海滩剖面呈上凹形。由具有最佳含水量的材料组成的陡崖与组成材料干燥程度偏离最佳值的陡崖相比，其顶部后退量减少。陡崖顶部的后退速率随有效内聚力的增加而降低。对于给定的有效内聚力，后退速率受相对密度的显著影响。对于由较松散土壤组成的陡崖，有效内聚力对后退速率的影响明显大于由较密实组成材料的陡崖。此外，还对细粒含量、相对密度和含水量变化对后退速率影响的不确定性进行了量化。