中国与西非桥梁设计洪水计算方法的比较分析

Comparison and Analysis of Bridge Design Flood Calculation Methods Between China and West Africa

为减少跨河桥梁设计洪水不确定性带来的水害隐患,比较分析了多种水文频率分布线型和由设计暴雨推算设计洪水流量的方法在西部非洲(西非)的适用性。对比了Gumbel与P-Ⅲ型分布对雨量样本频率的拟合优度,分析了Office de la Recherché Scientifique et Technique Outre-Mer(ORSTOM)与中国水利水电科学研究院(中国水科院)由设计暴雨推算设计洪水流量的原理和方法,对实际观测数据进行拟合,得到了ORSTOM方法的各参数计算方程。将多种方法用于西非工程实例,计算了设计洪水流量。结果显示:Gumbel和P-Ⅲ分布对西非雨量样本的频率拟合均能通过Kolmogorov-Smirnov检验,Gumbel分布的拟合更优。ORSTOM和中国水科院方法计算的设计洪水流量均合理,前者计算简单,后者计算值偏大11.92%。充分利用当地实测地表数据并采用多种方法计算和对比,可提高设计洪水计算结果的可靠性。

In order to reduce the hidden danger of water disaster caused by the uncertainty of design flood of river-crossing bridges,the applicability of various hydrological frequency distribution lines and the method of calculating design flood flow from design storm in West Africa was compared and analyzed.The fit goodness of Gumbel distribution and P-Ⅲdistribution to rainfall sample frequency was compared,and the principle and method of Office de la RecherchéScientifique et Technique Outre-Mer(ORSTOM)and the Chinese Academy of Water Resources and Hydropower Sciences(Chinese Academy of Water Sciences)to calculate the design flood flow from the design storm were analyzed.The actual observation data were fitted,and the calculation equations for the parameters of the ORSTOM method were obtained.Several methods were applied to the West Africa project to calculate the design flood flow.The results show that the frequency fitting of Gumbel and P-Ⅲdistributions to rainfall samples in West Africa can pass Kolmogorov-Smirnov test,and the Gumbel distribution fitting is better.The design flood flow calculated by the methods of ORSTOM and the Chinese Academy of Water Sciences is reasonable.The former is simple,while the latter result is larger by 11.92%.The reliability of design flood calculation results can be improved by making full use of local measured surface data and adopting various methods for calculation and comparison.