堰塞坝漫顶溃决过程及其受组成结构的影响

以四川茂县宗渠堰塞坝为原型，以几何相似比1〖DK(〗∶〖DK)〗100进行堰塞坝漫顶溃决模型试验。通过模型试验揭示了堰塞坝漫顶溃决的动力学过程，即下游坡面侵蚀、冲沟侵蚀、陡坎稳定侵蚀、陡坎加速侵蚀、陡坎减速侵蚀和常态化过程6个阶段。通过对比试验，揭示了坝体密度和级配特征对溃决速率以及溃口形式的影响机制，即坝体密度通过颗粒间剪切作用于溃决过程，密度更大的坝体溃决更慢，形成中轴线处窄浅的“矩形”溃口；坝体级配通过孤粒起动作用于溃决过程，级配更粗的坝体溃决更慢，形成中轴线处宽浅的“倒梯形”溃口。

Overtopping outburst process of barrier dam and influence by dam component and structure

We took the Zongqu Barrier dam as a prototype to conduct the overtopping outburst model texts with a geometry similar ratio of 1:100 and revealed dynamic processes of the overtopping outburst,namely surface erosion of downstream slope,gully erosion,constant headcut erosion,accelerated headcut erosion,decelerated headcut erosion and normal state erosion.Dam density and particle size distribution have significant influences on outburst rate and patterns through inter-particle shear and sole particle transportation respectively.Barrier dam with greater density will have a slower erosion rate,and a shallower and narrower rectangle breach at the axis;and barrier dam with coarser particle will also have a slower erosion rate,but a shallower and wider trapezia breach at the axis.