The accurate and rapid prediction of breach outflow rates of landslide dams is crucial for effective risk assessment and mitigation strategies. However, challenges arise due to the complexities associated with breaching mechanisms. In this study, 12 flume tests were conducted on landslide dams composed of various material types, including fine-grained, coarse-grained, well-graded, and gap-graded materials, each with two dry densities. This study comprehensively investigated erosion, deposition, and breach evolution, providing the foundation for the development of breach evolution models. A comprehensive logic diagram, focusing on shear stress and grain size distribution, was proposed to forecast the failure modes of landslide dams. The study also suggested a method to assess the longitudinal breach evolution based on the prediction of the Erosion Point (EP) and Deposition Point (DP), and to assess the lateral breach evolution by considering both steep and gentle breach side slopes. Our findings indicate that fine-grained materials undergo layer erosion, coarse-grained materials remain stable, well-graded materials develop erosion pits, and gap-graded materials are prone to piping. The existence of an interface can result in piping channels, even when the overall hydraulic gradient is insufficient to initiate piping. Incorporating the longitudinal slope angle and its influence on both driving and resisting forces into the traditional erosion rate equation can significantly enhance its accuracy, especially when coarse particles are present. Coarse particles play a pivotal role in erosion and deposition behavior and reshaping the breach evolution as the initiation of coarse particles is dominated by rolling instead of slipping in fine particles. Deposition on the downstream slope of a dam can significantly influence the longitudinal breach process, leading to changes in the downstream topography and grain size distribution. The proposed method for assessing longitudinal breach evolution unifies the previous methodologies by predicting the positions of EP and DP based on erosion and deposition.

中文翻译：

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基于水槽试验的不同坝料类型滑坡坝的侵蚀、沉积和溃口演化


准确、快速地预测滑坡坝的溃决流量对于有效的风险评估和缓解策略至关重要。然而，由于与破坏机制相关的复杂性，出现了挑战。在这项研究中，对由各种材料类型组成的滑坡坝进行了 12 次水槽试验，包括细粒、粗粒、良好级配和间隙级配材料，每种材料都有两种干密度。该研究全面研究了侵蚀、沉积和裂缝演化，为裂缝演化模型的发展提供了基础。提出了一个以剪应力和粒度分布为重点的综合逻辑图来预测滑坡坝的破坏模式。该研究还提出了一种基于侵蚀点（EP）和沉积点（DP）预测来评估纵向裂缝演化的方法，并通过考虑陡峭和平缓的裂缝边坡来评估横向裂缝演化。我们的研究结果表明，细粒材料会发生层侵蚀，粗粒材料保持稳定，级配良好的材料会形成侵蚀坑，间隙级配的材料容易出现管道。即使整体水力梯度不足以启动管道，界面的存在也会导致管道通道。将纵向坡度及其对驱动力和阻力的影响纳入传统的侵蚀速率方程可以显着提高其精度，特别是当存在粗颗粒时。粗颗粒在侵蚀和沉积行为以及重塑裂口演化中发挥着关键作用，因为粗颗粒的引发主要是滚动而不是细颗粒中的滑移。 大坝下游坡度的沉积可显着影响纵向溃口过程，导致下游地形和粒度分布的变化。所提出的评估纵向裂缝演化的方法通过根据侵蚀和沉积预测 EP 和 DP 的位置来统一以前的方法。