根据大朝山水电站表孔减压模型试验资料，结合原型观测有关资料，对台阶溢流坝掺气减蚀问题进行了分析研究。结果表明，利用表孔宽尾墩+台阶面的过流形式，可以解决台阶面大单宽过流掺气减蚀问题，台阶面水流近底掺气浓度最小在5%以上。高坝试验结果还表明，坝高增加20 m，台阶面水流掺气浓度沿程分布规律不变，即该掺气减蚀方法应用范围可推广至坝高131.0 m的台阶溢流坝。

This paper analyses the problem of flow aeration for mitigating cavitation on stepped　spillway. The study was conducted on the basis of the data of the spillway model test in a depression tank and the prototype observation for Daochaoshan Hydroelectric Station. The results showed that the large flow aeration to prevent cavitation on the stepped spillway can be solved by the flaring gate pier + stepped spillway. The air entrainment concentration on the bottom of stepped flow is not less than 5%. In the meantime, the results of experiment on higher dam showed that the streamwise air entrainment concentration distribution law does not vary as the dam height is increased by 20 m, so this method of flow aeration can be applied to the stepped spillway of dam height being 131 m.