Spur dikes are river training structures that have been extensively used worldwide for towards enhancing flood control and the stability of embankments and riverbanks. However, scour around spur dikes can be a major problem affecting their stability and hydraulic performance. The precise computation of temporal scour depth at spur dikes is very important for the design of economical and safe spur dikes. This study focuses on experimentally assessing the temporal variation of scour depth around a vertical wall spur dike and identifying the parameters, which mostly influence spur dike performance for a channel bed surface comprised of sand-gravel mixtures. In the current study, the authors did physical experiments in a flume based study to obtain new data, aimed at deriving a new predictive model for spur dike scour and comparing its performance to others found in the literature. It was found that the dimensionless temporal scour depth variation increases with an increase in (i) the threshold velocity ratio, (ii) the densimetric Froude number of the bed surface sediment mixture, (iii) the flow shallowness (defined as the ratio of the approach flow depth, y, to the spur dike’s transverse length, l), and (iv) the flow depth-particle size ratio. It is also concluded that the temporal scour depth variation in the sediment mixture is influenced by the non-uniformity of sediment and decreases with an increase in the non-uniformity of the sediment mixture. A new mathematical model is derived for the estimation of temporal scour depths in sand-gravel sediment mixtures. The proposed equation has been calibrated and validated with the experimental data, demonstrating a good predictive capacity for the estimation of temporal scour depth evolution.

丁坝是河道训练结构，已广泛用于增强防洪和堤防和河岸的稳定性。但是，绕堤坝冲刷可能是影响其稳定性和水力性能的主要问题。丁坝沿岸冲刷深度的精确计算对于经济，安全的丁坝设计非常重要。这项研究的重点是通过实验评估垂直壁丁坝周围冲刷深度的时间变化并确定参数，这些参数主要影响由砂砾混合料组成的河床层的丁坝性能。在当前的研究中，作者在基于水槽的研究中进行了物理实验，以获取新的数据，目的是为丁坝冲刷建立一个新的预测模型，并将其性能与文献中的其他模型进行比较。发现无量纲的时间冲刷深度变化随着（i）阈值速度比，（ii）床面沉积物混合物的密度Froude数，（iii）流动浅度（定义为流速比）的增加而增加。进水深度y，对丁坝的横向长度l），和（iv）流动深度-粒径比。还得出结论，沉积物混合物中的时间冲刷深度变化受沉积物不均匀性的影响，并且随着沉积物混合物不均匀性的增加而减小。推导了一个新的数学模型，用于估算砂砾混合物中的时间冲刷深度。所提出的方程式已经过校准，并通过实验数据进行了验证，证明了其对估算时间冲刷深度演化具有良好的预测能力。