Abstract: Weak interlayer towards downstream was contained in the Wuma dam foundation and the downstream channel was S shaped. The high-speed flow from the bottom outlet dashed against the dam toe and the rock downstream which threatened the safety of the dam. Thus, the trajectory bucket type energy dissipation was replaced by bottom-flow energy dissipation in design optimization, worth reference.

Key words: outlet for flood release and sand discharge, trajectory bucket type energy dissipation, scour hole, bottom-flow energy dissipation, diffusion stilling basin

摘要： 五马水库坝址坝基存在倾向下游的软弱夹层，下游河道呈S型，底孔出口挑射高速水流会冲击坝脚和下游山体，对大坝造成严重威胁。鉴于此，将泄洪冲沙底孔出口由挑流调整为底流消能。笔者对优化设计加以总结，以资借鉴。

关键词: 泄洪冲沙底孔, 挑流消能, 冲坑, 底流消能, 扩散式消力池