陈萌 翁朝晖 范杨臻 余明辉 魏红艳

摘要：截洪溝洪峰流量是截洪沟设计的重要参数。通过工程实例分析比较三种截洪沟洪峰流量计算方法，研究了降雨历时、山洪容重和重现期对三种方法洪峰流量的影响，并分析了各方法主要影响因素的显著程度。结果表明，对于工程实例，方法1（水土保持工程设计规范）和方法3（室外排水设计规范）的结果较接近，更偏安全。洪峰流量随降雨历时的增大逐渐减小，两者呈幂函数关系；洪峰流量随山洪容重的增大而增大，两者基本呈指数函数关系；洪峰流量随重现期的增大基本呈对数增长趋势。方法1和方法3各因素的影响程度从大到小排序为汇流面积>降雨历时>径流系数>重现期；方法2（开发建设项目水土保持技术规范）各因素的影响程度从大到小排序为汇流面积>径流系数>重现期>高含沙山洪容重。

关键词：截洪沟；洪峰流量；降雨历时；重现期；山洪容重；径流系数；汇流面积

中图分类号：TV122文献标志码：A文章编号：16721683（2018）03005108

Study and comparison of calculation methods for flood peak discharge of cutoff ditch in small watershed

CHEN Meng1，WENG Zhaohui1，FAN Yangzhen2，3，YU Minghui2，WEI Hongyan2

（1.Hubei Provincial Water Resources and Hydropower Planning Survey and Design Institute， Wuhan 430064，China；

2.State Key Laboratory of Water Resources and Hydropower Engineering Science，Wuhan University，Wuhan

430072， China；3.Hubei Water Resources Research Institute， Wuhan 430070，China）

Abstract：The flood peak discharge of a cutoff ditch is an important parameter in cutoff ditch design.In this paper，we compared three calculation methods for flood peak discharge of cutoff ditches based on a project case.We studied the influence of rainfall duration，unit weight of torrential flood，and recurrence interval on flood peak discharge，and analyzed the significance degree of the influence factors.It was found that Method 1 （Code for design of soil and water conservation projects） and Method 3 （Code for design of outdoor drainage projects） had similar results for the project case and both leaned towards safety.The flood peak discharge would gradually decrease with the increase of rainfall duration，with a power function relation between them.The peak discharge would increase with the increase of unit weight of torrential flood，with an exponential function relation between them.The peak discharge showed a trend of logarithmic growth with the increase of recurrence interval.Catchment area had the largest influence on flood peak discharge for Methods 1 and 3，followed by rainfall duration and runoff coefficient，while the influence of recurrence interval on flood peak discharge was the smallest. Catchment area had the largest influence on flood peak discharge for Method 2 （Technical code on soil and water conservation of development and construction projects），followed by runoff coefficient and recurrence interval，while the influence of unit weight of torrential flood on flood peak discharge was the smallest for Method 2.

Key words：cutoff ditch；peak discharge；rainfall duration；recurrence interval；unit weight of torrential flood；runoff coefficient；catchment area

截洪沟是为了拦截排水地区坡面上部的径流而修建的排水沟道，用来保护某一地区或某项工程免受洪水造成的渍涝和冲刷。截洪沟的设计流量是一个重要的参数，它是确定截洪沟断面尺寸的重要依据。由于截洪沟的洪水流量过程线一般峰高量小，历时短，因此，可采用洪峰流量作为截洪沟的设计流量[1]。

受降雨强度、地表粗糙度、山坡坡度、土壤结构等因素的影响，坡面产汇流是一个极为复杂的过程[26]。因此，小流域……