Catastrophic breaches of water and mine waste retaining impoundments in recent history have emphasized the severity and consequences to the downstream environment. In this study, the applicability and suitability of the XBeach numerical model for modelling earth dam failures driven by overtopping with water is explored by detailed comparison with controlled experimental data. The XBeach model is applied to simulate laboratory-scale breaches caused by overtopping failure of dams constructed with uniform sand at the Queen's University Landslide Flume by Walsh et al. (2021a). The model sensitivity to boundary conditions for different virtual flume sizes, different sediment transport equations that influence erosion rates, and the process of avalanching are investigated. The model results are in best agreement with laboratory measurements when the Soulsby-van Rijn sediment transport formulation is used, which depends on grain size, and the avalanching module is activated, indicating the importance of these processes. The model is also run for different dam geometries to investigate the influence of upstream slope angle, which is relevant for tailings dam breach analyses. The results indicate that for flatter slopes the model is in closer agreement with observations of the peak discharge, while for steeper slopes the model results are better for breach duration time. Overall, XBeach provides promising results for the prediction of the dam breach outflow hydrograph at the laboratory scale and has potential to improve understanding of earth dam failure outcomes with further investigation.

中文翻译：

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使用 XBeach 模拟实验室规模土坝的漫顶溃决

近代历史上发生的灾难性水坝破坏和矿山废物蓄水池的破坏凸显了下游环境的严重性和后果。在这项研究中，通过与受控实验数据的详细比较，探讨了 XBeach 数值模型在模拟水漫溢引起的土坝破坏方面的适用性和适用性。Walsh 等人采用 XBeach 模型来模拟在女王大学滑坡水槽中使用均匀沙子建造的大坝漫溢破坏导致的实验室规模的决口。（2021a）。研究了模型对不同虚拟水槽尺寸的边界条件、影响侵蚀速率的不同泥沙输送方程以及雪崩过程的敏感性。当使用 Soulsby-van Rijn 沉积物输送公式（取决于颗粒尺寸）并且雪崩模块被激活时，模型结果与实验室测量结果最为一致，表明这些过程的重要性。该模型还针对不同的坝几何形状运行，以研究上游坡度角度的影响，这与尾矿坝溃决分析相关。结果表明，对于较平坦的斜坡，模型与峰值流量的观测结果更加一致，而对于较陡的斜坡，模型结果对于溃口持续时间而言更好。总体而言，XBeach 为实验室规模的溃坝流出过程线预测提供了有希望的结果，并有可能通过进一步调查提高对土坝溃坝结果的了解。