Abstract

This paper presents a numerical model study on the ice cover effect on bank stability in non-cohesive alluvial channels. The model consists of a coupled two-dimensional finite element unsteady hydrodynamic model with bank erosion and mass failure processes for open water and ice-covered conditions. The associated morphological change is modeled with non-equilibrium sediment transport, including the side slope effect on bed load transport. The model adopts two sets of repose angles for emerged and submerged bank materials in analyzing non-cohesive bank mass collapses and redistributions. The model is validated with published laboratory experiments on bank retreat caused by dam-break flow and equilibrium cross-section evolution and showed improvements over existing numerical models. Simulated results showed that the ice cover caused larger bank retreats and bed depositions and slower channel cross-sectional change due to the reduced bed shear stress and the increased flow depth.

Article Highlights

A bank stability model is developed by coupling the unsteady hydrodynamics, non-equilibrium sediment transport, and bank erosion and mass failure processes.

The model is validated with published laboratory experiments and other models.

The ice-covered flow causes larger riverbank retreats and slower cross-sectional changes than that of the open channel flow.

中文翻译：

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模拟冰盖对河道岸稳定性的影响

摘要

本文提出了一个数值模型研究冰盖对非粘性冲积河道岸堤稳定性的影响。该模型由一个耦合二维有限元非定常流体动力学模型组成，该模型具有开阔水域和冰盖条件下的堤岸侵蚀和质量破坏过程。相关的形态变化是用非平衡泥沙运输模拟的，包括边坡对床载运输的影响。该模型采用浮水和沉水岸材料两组休止角分析非粘性岸体坍塌和重新分布。该模型已通过已发表的关于由溃坝流和平衡截面演变引起的堤岸退缩的实验室实验进行验证，并显示出对现有数值模型的改进。

文章重点

通过耦合非定常流体动力学、非平衡泥沙输运以及堤岸侵蚀和质量破坏过程，开发了堤岸稳定性模型。

该模型已通过已发表的实验室实验和其他模型进行验证。

冰覆盖的水流比明渠水流造成更大的河岸退缩和更慢的横截面变化。