关于堤坝坝顶高程计算中安全加高的讨论

Discussion on Safety Freeboard in Calculating Crest Elevation of Levee

摘要: 安全加高是确定堤坝坝顶高程的重要参数，直接影响防洪安全和经济性。本文基于现行规范和防洪工程资料，分析讨论了堤坝工程设置安全加高的必要性、取值原则和方法。研究表明，影响洪水漫顶的安全因素，基本上都可以定量确定，计算静水位以上的超高时没有必要再单独考虑安全加高。安全加高的规定与当前防洪工程发展形势不适应，与欧美发达国家通行做法不一致。建议构建柔性综合防洪体系，取消安全加高的规定，安全超高由浪高和风壅增高直接确定。

Abstract: Safety freeboard, one of the important parameters to determine the crest elevation of levee, de-termines the safety and economy of flood control engineering in a great way. Based on the current design codes and some research materials, the necessary and selections of the safety freeboard corresponding to different structures and different typical flood are studied. The results show that the main factors of flood overtopping can be quantitatively determined, so there is no need to es-timate safety freeboard in calculating dam height above static water level. Now, stipulation of safety freeboard is in some contradiction with flood control development and not consistent with the prevailing practice in western developed countries. It is necessary to revise applicable design codes and standards. When constructing a flexible comprehensive flood control system and canceling safety freeboard in calculating crest elevation, safety height is just equal to sum of heights by waves and the wind.