尾矿库漫顶溃决动态演化及溃口展宽模型试验

为研究尾矿库漫顶溃决动态演化过程与溃口发展机理及规律，通过3组相似模型试验，对溃口展宽过程和演变机理进行了系统分析，提出了尾矿坝漫顶模式下溃口展宽速率的幂函数公式，并讨论了库水位上升阶段浸润线的变化过程及溃决阶段不同浸润线埋深条件下流速、流量、溃口宽度的变化过程。研究结果表明：尾矿坝的溃决过程可分为坝面漫流与冲沟形成、坝体崩塌与溃口快速扩张及稳定泄流3个阶段；浸润线埋深对流量、流速及溃口最终宽度有较大影响，排渗失效时峰值流量及溃口最终宽度接近正常排渗时的1.5倍，峰值流速可达1.2～1.3倍；降低浸润线高度可以延缓溃决泥石流到达下游的时间，紧急撤离时间也可延长3 min左右；提出的幂函数公式计算值与实测值吻合较好。

Dynamic evolution and breach spreading test for tailings pond overtopping failure

To investigate the dynamic process of tailings pond overtopping failure and the mechanism of breach development, three sets of comparable model tests were conducted to systematically analyze the process of breach spreading and the evolution of the breach. A power function formula of the breach spreading rate under overtopping failure mode was proposed. The process of infiltration line change during the reservoir water level rise stage and the change of flow velocity, flow rate, and breach width under different infiltration line depth conditions during the breaching stage was discussed. The results show that the breaching process of tailings dams can be subdivided into three stages, which are diffuse flow and gully formation, dam collapse and rapid expansion of the breach, and stable flow release. The depth of the infiltration line has a major impact on the flow rate, flow velocity, and the final width of the breach. The peak flow rate and the final width of the breach when the seepage fails are 1.5 times those of the normal discharge, and the peak flow velocity can be 1.2 to 1.3 times that of the normal discharge. Reducing the height of the infiltration line can delay the time for the debris flow reaching the downstream of the breached dam, which can extend the emergency evacuation time by about 3 min. The calculated values of the power function formula match the measured values well.