Abstract The erosion of marine sediments, although difficult to predict, can lead to important implications in offshore engineering, sedimentology and coastal management. Continued research is, therefore, warranted to compile high-quality erosion data from which to develop models to better predict the erosion resistance of different types of marine sediments. In this paper, dimensional analysis is performed to express the threshold shear stress as a function of a selection of soil properties that are commonly linked to the erosion process of sediments. To identify the dominant dimensionless group, an experimental investigation on the erosion threshold was carried out using fine-grained sediments that were systematically prepared to ensure variations in (i) particle size distribution (i.e. fines content), (ii) bulk density, and (iii) hydraulic permeability. The samples included silica, carbonate and marine sediments, each of which are expected to have limited or no clay-mineral content. The measurements were analysed and compared with existing literature and predictive models. It was found that marine sediment samples with limited fines content showed good agreement with the empirical Shields curve, irrespective of particle size distribution, bulk density and permeability. In contrast, for finer marine sediment it was found that variations in these soil properties modify the threshold shear stress away from the Shields curve. Across each of these parameters only permeability appeared to independently correlate with the observed range of threshold measurements. Motivated by this finding, a model is introduced to predict the threshold shear stress as a function of permeability and the reference erosion rate that is used to define when the threshold is reached. The resulting expression is shown to quantitatively explain the experimental data and is found to also agree with existing data from the literature for quartz sediments with a wide range in fines content. An apparent advantage of the new model is that it is consistent with existing studies that identify variations in threshold shear stress due to changes in bulk soil parameters – including fines content and bulk density – since each of these parameters also affect permeability.

中文翻译：

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渗透率对细粒沉积物侵蚀阈值的影响

摘要 海洋沉积物的侵蚀虽然难以预测，但对近海工程、沉积学和海岸管理具有重要意义。因此，有必要继续研究以编制高质量的侵蚀数据，从中开发模型以更好地预测不同类型海洋沉积物的侵蚀抵抗力。在本文中，进行量纲分析以将阈值剪切应力表示为通常与沉积物侵蚀过程相关的一系列土壤特性的函数。为了确定主要的无量纲组，使用细粒沉积物对侵蚀阈值进行了实验研究，这些沉积物被系统地制备以确保（i）粒度分布（即细粒含量），（ii）体积密度，(iii) 透水性。样品包括二氧化硅、碳酸盐和海洋沉积物，预计每一种都含有有限的粘土矿物或不含粘土矿物。对测量结果进行分析并与现有文献和预测模型进行比较。结果发现，无论粒度分布、堆积密度和渗透率如何，具有有限细粒含量的海洋沉积物样品与经验盾牌曲线非常吻合。相比之下，对于更细的海洋沉积物，发现这些土壤特性的变化会修改远离盾牌曲线的阈值剪切应力。在这些参数中的每一个中，只有渗透率似乎与观察到的阈值测量范围独立相关。受这一发现的启发，引入了一个模型来预测作为渗透率函数的阈值剪切应力和用于定义何时达到阈值的参考侵蚀率。所得表达式被证明可以定量解释实验数据，并且发现也与文献中关于细粒含量范围广泛的石英沉积物的现有数据一致。新模型的一个明显优势是，它与现有研究一致，这些研究确定了由于大块土壤参数（包括细粒含量和体积密度）的变化而导致的阈值剪应力变化，因为这些参数中的每一个都会影响渗透性。所得表达式被证明可以定量解释实验数据，并且发现也与文献中关于细粒含量范围广泛的石英沉积物的现有数据一致。新模型的一个明显优势是，它与现有研究一致，这些研究确定了由于大块土壤参数（包括细粒含量和体积密度）的变化而导致的阈值剪应力变化，因为这些参数中的每一个都会影响渗透性。所得表达式被证明可以定量解释实验数据，并且发现也与文献中关于细粒含量范围广泛的石英沉积物的现有数据一致。新模型的一个明显优势是，它与现有研究一致，这些研究确定了由于大块土壤参数（包括细粒含量和体积密度）的变化而导致的阈值剪应力变化，因为这些参数中的每一个都会影响渗透性。