We set up a laboratory experiment to reproduce flow‐induced bank erosion and bank collapse and to study the role of bank height (H_b) and near‐bank water depth (H_w) on bank stability. Five laboratory experiments were conducted in a plexiglass‐walled soil tank, using silt collected from natural tidal channel banks (D₅₀ = 75 μm). During each experiment, the bank was subject to a steady and uniform flow. We measured the variations in total soil stress, pore water pressure (when negative, called matric suction), and water content inside the bank and flow velocity and suspended‐sediment concentration upstream and downstream of the bank. Results show that the experiments can reproduce four failure types commonly observed in nature including toppling, tensile and shear failures, and erosion and failure driven by loss of matric suction. The patterns of bank failure can be related to H_b/H_w. For large H_b/H_w (> = 2), we observe a cantilever‐shape bank profile. For small H_b/H_w (<2), we first observe cracks on the bank top, followed by shear failures along a vertical or inclined surface separating the cantilever block up from the bank top. When accounting for our results in the context of previous experimental studies, we find a transition point characterized by a maximum normalized bank retreat rate. For toppling failures, we also find a positive correlation between the ratio H_b/H_w and the geometrical contribution to bank retreat from bank collapse (C_bc). Our research quantifies the role of H_b/H_w on bank collapse, bank retreat rate, and the overall C_bc.

中文翻译：

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岸塌的实验室实验：岸高和近岸水深的作用

我们建立了一个实验室实验，以重现水流引起的河岸侵蚀和河岸坍塌，并研究河岸高度（H _b）和近岸水深（H _w）对河岸稳定性的作用。在有机玻璃墙的土壤罐中进行了五项实验室实验，使用的是从天然潮汐河道堤岸收集的淤泥（D ₅₀ = 75μm）。在每个实验中，堤岸都要承受稳定而均匀的流量。我们测量了土壤总应力，孔隙水压力（负值时称为基质吸力），河岸内部的水含量以及河岸上游和下游的流速和悬浮沉积物浓度的变化。结果表明，该实验可以重现自然界中常见的四种失效类型，包括倾倒，拉伸和剪切失效，以及由于基质吸力损失而引起的侵蚀和失效。银行倒闭的模式可能与H _b / H _w有关。对于大的H _b / H _w（> = 2），我们观察到一个悬臂形的堤岸轮廓。对于小H _b/ H _w（<2），我们首先观察到堤岸顶部出现裂缝，然后沿着垂直或倾斜表面进行剪切破坏，将悬臂梁与堤岸顶部分开。在先前的实验研究中考虑我们的结果时，我们发现了一个以最大标准化银行撤退率为特征的过渡点。对于倾覆失败，我们还发现比率H _b / H _w与从堤岸坍塌（C _bc）对堤岸撤退的几何贡献之间存在正相关。我们的研究量化了H _b / H _w在银行倒闭，银行退缩率以及总体C_BC。