This study employs a two-dimensional sediment-water model to simulate and analyze sandy embankment breach floods. To account for complex flow patterns and sediment transport characteristics post-breach, the model is constructed based on the two-dimensional shallow water equations (SWEs). It employs a three-element weighted essentially oscillation-free Roe scheme for discretization and incorporates a non-equilibrium total sediment transport model to simulate scouring processes at the breach. A stability criterion for the breach is established by integrating hydraulic shear stress with soil shear strength, while the breach expansion mechanism is described using a scour- collapse lateral widening model. Experimental results demonstrate high consistency between simulated data and flume test data, validating the model′s capability to simulate key variables such as water level, flow velocity, and sediment gradation during sandy embankment failure. Notably, the model effectively captures flow parameters at the breach location that are difficult to measure directly. The proposed simulation method provides a high-precision tool for assessing sandy embankment failure risks, offering significant reference value for flood control safety design and disaster mitigation strategy formulation.

dam failure, flood simulation, two-dimensional sediment-water model, shallow water equations, non-equilibrium total sediment transport, breach scouring

本研究针对砂质堤坝，采用二维水沙模型开展溃决洪水模拟与分析。考虑溃堤后复杂流态与泥沙输运特性，基于二维浅水方程（SWEs）构建模型，通过三元素加权本质无振荡Roe格式离散化处理，并引入非平衡全沙输运模型模拟溃口冲刷过程。结合水流剪切力与土壤抗剪强度，建立溃口稳定状态判据，采用冲刷坍塌侧向拓宽模式描述溃口扩展机制。试验结果表明，模拟数据与水槽试验数据高度吻合，验证了模型对砂质堤坝溃决过程中水位、流速、泥沙级配等关键变量的模拟能力，尤其能有效捕捉溃口处较难测量的流态参数。研究提出的模拟方法为砂质堤坝溃决风险评估提供了高精度工具，对工程防洪安全设计及减灾措施制定具有重要参考价值。

堤坝溃决, 洪水模拟, 二维水沙模型, 浅水方程, 非平衡全沙输运, 溃口冲刷