Abstract

Fluvial erosion due to hydraulic force and bank failure under the influence of gravity are the two physical processes of riverbank erosion. This paper presents a new, simple, semi-analytical method to estimate the rate of fluvial erosion of non-cohesive riverbanks caused by hydraulic force. The derived equation is built based on the critical flow velocity concept, rather than the commonly used shear stress approaches. Because the distribution of the shear stress of a side wall varies considerably with the side wall’s cross-sectional profile, it is difficult to estimate the shear stress distribution along a river bank. In contrast, the cross-sectional contours of flow velocity close to the side wall are parallel to the wall to some extent, which suggests that the flow velocity is more reliable and more easily measured in comparison to the shear stress. Large-scale laboratory experiments were conducted to evaluate the critical-velocity-based model. The calculated results agree well with the measured data. This semi-analytical approach is promising for estimating the fluvial bank erosion rate in the field.

中文翻译：

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计算非粘性河岸冲刷率的一种新的半分析方法

摘要

水力作用引起的河道侵蚀和重力作用下的河岸破坏是河岸侵蚀的两个物理过程。本文提出了一种新的，简单的，半分析的方法来估算由水力引起的非粘性河岸的河道侵蚀速率。推导方程是基于临界流速概念而不是常用的剪应力方法建立的。因为侧壁的切应力的分布随侧壁的横截面轮廓而有很大的变化，所以很难估计沿河岸的切应力分布。相反，靠近侧壁的流速横截面轮廓在某种程度上与壁平行，这表明与剪切应力相比，流速更可靠且更容易测量。进行了大规模的实验室实验，以评估基于临界速度的模型。计算结果与实测数据吻合良好。这种半分析方法有望用于估算该地区的河岸侵蚀率。