堰塞坝坝料级配范围宽、不均匀性强，漫顶溃坝水流强非恒定特性明显，揭示该水力条件下的宽级配土石料输移特性及冲刷机理成为堰塞坝溃坝研究的关键。为此，本项目首先通过开展宽级配土石料强非恒定流冲刷试验，揭示宽级配土石料输移规律，建立强非恒定流冲刷条件下的非平衡输沙理论模型。然后，利用溃坝离心模型试验系统，开展不同坝料状态及离心加速度的堰塞坝漫顶溃坝模型试验，定量研究坝料状态参量对溃口的横向扩展、纵向下切、坝体背水坡溯源冲刷过程以及溃口流量过程的影响规律，通过外延分析进一步揭示高堰塞坝漫顶溃决宏观机理。最后，建立能够合理描述堰塞坝漫顶破坏时溃口发展规律和溃口洪水流量过程的数学模型并建议相应的计算方法，为合理评价堰塞坝溃决致灾后果，科学制定溃坝洪水应急预案提供理论支持。

The material of barrier dam with a wide range of gradation is strong heterogeneous, and the flow of overtopping is unsteady obviously. In this hydraulic condition, erosion mechanism of wide grading earth rockfill materials and its transport theory has become the key during the study of barrier dam break. For this, through scouring experiment of wide grading earth rockfill materials under strong unsteady flow, rule of transport is revealed, and nonequilibrium sediment transport model under condition of strong unsteady flow is established first. Then, by means of centrifugal model test, influences of different dam material parameters on the vertical erosion, transverse expansion and regression erosion of breach are quantitative researched, and macroscale mechanism of high barrier overtopping is revealed by extending analyses. Finally, a numerical model and the corresponding calculation method are proposed which can correctly depict the process of breach expansion and overtopping flow. The barrier dam break model can be used to evaluate the consequences due to dam break and provide theoretical support for emergency plans and treatment.