Arora Sukhjeet, Kumar Bimlesh
Department of Civil Engineering, IIT Guwahati, Guwahati, India.
Sci Rep. 2025 Mar 26;15(1):10389. doi: 10.1038/s41598-025-95524-7.
Unregulated sediment dredging near riverbanks considerably increases the risk of bank failures. This study examines how the proximity of sediment mining pits influences riverbank stability by conducting controlled laboratory flume experiments on three riverbank slopes: 25°, 31°, and 40°. The analysis considers three scenarios-upstream pit, instream pit, and no-pit conditions while evaluating key hydraulic parameters, including mean streamwise velocity, Reynolds shear stress (RSS), and turbulent kinetic energy (TKE). These measurements provide insights into flow dynamics, turbulence characteristics, and morphological changes. The results indicate that steeper slopes experience higher erosion risks. The 40° slope exhibits velocity increases of up to 35% and TKE peaks reaching 40% above baseline levels when a pit is in close proximity, leading to severe toe scouring and sediment detachment. In contrast, the 25° slope maintains hydraulic equilibrium, limiting velocity increases to 15% and experiencing minimal turbulence-induced erosion, making it the most stable configuration for reducing mining-related impacts. The 31° slope, corresponding to the angle of repose, strikes a balance between sediment mobility and stability but requires localized reinforcements to mitigate erosion. These findings highlight the need for well-regulated sediment mining practices and targeted riverbank stabilization strategies to reduce the growing risk of bank failures.
河岸附近无节制的沉积物疏浚会大幅增加河岸坍塌的风险。本研究通过对25°、31°和40°这三种河岸坡度进行控制实验室水槽实验，研究沉积物开采坑的距离如何影响河岸稳定性。分析在评估包括平均流向速度、雷诺剪应力（RSS）和湍动能（TKE）等关键水力参数时考虑了三种情况——上游坑、河中风坑和无坑条件。这些测量为水流动力学、湍流特性和形态变化提供了见解。结果表明，坡度越陡，侵蚀风险越高。当坑靠近时，40°坡度的流速增加高达35%，湍动能峰值比基线水平高出40%，导致严重的坡脚冲刷和沉积物脱离。相比之下，25°坡度保持水力平衡，将流速增加限制在15%，且经历的湍流诱发侵蚀最小，使其成为减少采矿相关影响的最稳定构型。31°坡度对应休止角，在沉积物流动性和稳定性之间取得平衡，但需要局部加固以减轻侵蚀。这些发现凸显了对沉积物开采实践进行严格监管以及采取有针对性的河岸稳定策略以降低日益增长的河岸坍塌风险的必要性。
