Modeling the erosion of cohesive clay coasts
Modeling the erosion of cohesive clay coasts
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DOI：
10.1016/j.coastaleng.2008.07.001
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发表时间：
2009
影响因子：
4.4
通讯作者：
A. Trenhaile
中科院分区：
文献类型：
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作者：
A. Trenhaile
建立了粘结粘土海岸在宏观和非潮汐环境下的侵蚀模型。该模型与以前的模型有一些相同的特征，包括由波浪产生的底部剪切应力对裸露粘土表面的侵蚀，以及由磨损对可移动的沉积物覆盖表面的侵蚀。然而，它与以前的模型在几个重要方面有所不同。粘土地基海滩在不同波浪条件下的形态动力学是基于先前开发的岩石海岸平台海滩模型。沿海滩剖面的沉积物厚度定期计算，并与盛行波条件下该位置可能移动的最大厚度进行比较。必要时，根据底部波纹的发生和形态来确定波浪摩擦系数。除了磨损和波浪引起的剪切应力对粘土底部的影响外，波浪冲击在断崖脚和潮间带平台上产生的应力所产生的侵蚀也使用从硬岩海岸模型中导出的表达式来计算。潮汐由计算出的潮汐持续时间值来表示，即每年水位在每0.1米垂直间隔内下降的时间。水深随波浪的形成和沉降条件而变化。进行了几次初步模型运行。剖面在海底带呈凹形，在潮间带呈近似线性。当他们向陆地迁移时，平衡轮廓得以保持。
A model was developed to study the erosion of cohesive clay coasts in macro- to non-tidal environments. The model shares some of the characteristics of previous models, including the erosion of bare clay surfaces by wave generated bottom shear stresses, and of mobile, sediment-covered surfaces by abrasion. It differs from previous models, however, in several important ways. The morphodynamics of beaches with clay foundations, under different wave conditions, are based on a previously developed model for beaches on rocky shore platforms. Sediment thickness along a beach profile is calculated at regular intervals and compared with the maximum thickness that could be moved at that location under prevailing wave conditions. Wave friction factors are determined, where necessary, according to the occurrence and morphology of ripples on the bottom. In addition to abrasion and the effect of wave induced shear stresses on the clay bottom, erosion by stresses generated by wave impact at the bluff foot and on the intertidal platform is calculated using an expression derived from hard rock coastal models. Tides are represented by their computed tidal duration values, the amount of time each year that the water level falls within each 0.1 m vertical interval. Water depths are modified by wave setup and set-down conditions. Several preliminary model runs were made. The profiles were concave in the submarine zone and roughly linear in the intertidal zone. Equilibrium profiles developed which were maintained as they migrated landwards.