CAJ | 학술논문

我国《规范》推荐的梯级水库下游设计洪水计算方法，在实际工作中采用经验和概化处理，既影响成果的科学合理性，亦影响成果精度。本文以 Copula函数理论为基础，构造了水库断面洪量与区间洪量的联合分布，推求了条件概率函数的显式表达式，提出了基于 Copula函数的改进离散求和法，通过直接对条件概率曲线进行离散，克服了《规范》中离散求和法需要进行变量独立性转换的问题。以清江流域梯级水库下游设计洪水为例，分析比较地区组成法、离散求和法和基于 Copula函数的改进离散求和法所得设计成果。结果表明，几种方法所推求的设计值差别不大，但改进的离散求和法所得结果稍微偏大，这是由于该法考虑了各分区变量之间的内在联系，结果比较合理和偏安全；受上游梯级水库调蓄的影响，高坝洲断面千年一遇设计洪水的削峰率高达40%以上。
아국《규범》추천적제급수고하유설계홍수계산방법，재실제공작중채용경험화개화처리，기영향성과적과학합이성，역영향성과정도。본문이 Copula함수이론위기출，구조료수고단면홍량여구간홍량적연합분포，추구료조건개솔함수적현식표체식，제출료기우 Copula함수적개진리산구화법，통과직접대조건개솔곡선진행리산，극복료《규범》중리산구화법수요진행변량독립성전환적문제。이청강류역제급수고하유설계홍수위례，분석비교지구조성법、리산구화법화기우 Copula함수적개진리산구화법소득설계성과。결과표명，궤충방법소추구적설계치차별불대，단개진적리산구화법소득결과초미편대，저시유우해법고필료각분구변량지간적내재련계，결과비교합리화편안전；수상유제급수고조축적영향，고패주단면천년일우설계홍수적삭봉솔고체40%이상。
The design flood estimation methods recommended by Chinese guidelines for downstream area of cascade reservoirs can only be used with experiences and simplifications in engineering practice, which may affect the precision and scientific rationality of the final results. In this study, Copula function was used to establish the joint distribution of flood volumes between dam-site section and interval basin. A mod?ified discrete summation method was proposed based on the conditional distribution derived by Copula func?tion. The proposed method, which discretizes the conditional distribution curve directly, can overcome the shortcomings of traditional discrete summation method and do not need independence transformation. The de?sign flood for downstream area of the Qingjiang cascade reservoirs was estimated by area composition meth?od, discrete summation method and Copula-based modified discrete summation method. The Comparison re?sults show that there are little differences of design flood values estimated by these methods. The flood quantile estimated by the proposed method is a little larger than those of other methods since it has consid?ered the inner correlation of floods in different regions, which is much safer and reasonable. Besides, the 1000-year design peak discharge of the Gaobazhou dam-site has been cut over 40 % due to the regulation of upstream cascade reservoirs.