Despite the widespread application of spur dikes in river training projects, the performance of the structure during flood events and its impacts on unsteady flow conditions have rarely been studied. In this experimental investigation, the influences of twelve unsubmerged unilateral and bilateral spur dike layouts on upstream flow conditions during flood movements were examined. Three hydrographs with varying unsteadiness intensities were generated and applied to all layout tests, including the no-spur condition for comparison purposes. The results revealed that discharge directly affected changes in flow depth upstream of the spur dike, while the flow rate trend exerted inverse influences. The Keulegan-Carpenter number was modified to assess the impact of unsteadiness intensity on the rating curve loop. Stage hysteresis analysis demonstrated an increase of more than thirty times compared to the no-spur scenario, highlighting the elevated risk of flooding in the upstream reach while delaying peak flood arrival time. This has implications for flood risk management and warning programs. The results underscore the significance of considering not only peak discharge but also unsteadiness intensity in spur dike design.

中文翻译：

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丁坝布局对洪水波运动期间上游水流条件的影响

尽管丁坝在河流整治工程中得到广泛应用，但洪水事件期间结构的性能及其对不稳定水流条件的影响却很少被研究。在这项实验研究中，研究了洪水运动期间十二个未淹没的单边和双边丁坝布局对上游水流条件的影响。生成了三个具有不同不稳定性强度的过程线，并将其应用于所有布局测试，包括用于比较目的的无杂散条件。结果表明，流量直接影响丁坝上游水流深度的变化，而流量趋势则产生相反的影响。修改了 Keulegan-Carpenter 数以评估不稳定强度对评级曲线环的影响。阶段滞后分析表明，与无杂波情景相比，增加了三十多倍，突显了上游河段洪水风险增加，同时延迟了洪峰到达时间。这对洪水风险管理和预警计划具有影响。结果强调了丁坝设计中不仅考虑峰值流量而且考虑不稳定强度的重要性。