摘要
黄河下游洪水演进过程受来水来沙条件和河床断面形态的共同制约,但目前研究较少考虑断面形态调整的影响。以黄河下游游荡段为研究对象,基于实测资料分析和一维非恒定水沙耦合数学模型计算,研究在相同平滩断面面积下不同断面形态对洪水演进过程的影响。实测资料分析结果表明:当洪峰量级接近时,窄深河段的洪水传播速度较快,传播时间较短;洪水涨率与河相系数负相关(确定性系数R^(2)=0.91)。数值模拟结果表明:在进口水沙过程相同的条件下,与1992年宽浅河道相比,2003年窄深河道下花园口至高村游荡段洪水传播时间由64 h缩短至21 h,洪峰流量削减21%,河段淤积量减少34%。窄深断面形态不仅能缩减游荡段洪峰传播时间,同时有利于减缓河道淤积。
Flood routing process is constrained by the inflow and sediment conditions and channel geometry,while the influences of the latter is seldom analyzed.Based on the measured hydraulic data and a coupled 1D morphological model,the braided reach of the Lower Yellow River was selected as the study section to analyze the influences of adjustment of channel geometry to the flood routing in the case of same magnitude of bankfull area.The results of the analysis of measured hydrological data indicate that when the magnitude of flood peak discharge is slightly changed,the velocity of flood propagation is larger in the narrower and deeper cross section with smaller geomorphic coefficient,and the corresponding propagation time is smaller;the rising rate of floodwater level shares a negative correlation with geomorphic coefficient,with the determination coefficient equals to 0.91;numerical simulation by 1D model shows that keeping the upstream conditions unchanged,the flood propagation time of the channel with smaller geomorphic coefficient in 2003 is reduced from 64 h to 21 h,and the flood peak dis⁃charge and the deposition volume reduced by 21%and 34%respectively,which indicates that the channel with narrower and deeper geometry can reduce the time of flood propagation and relive the channel aggradation as well.
作者
程亦菲
夏军强
周美蓉
邓珊珊
CHENG Yifei;XIA Junqiang;ZHOU Meirong;DENG Shanshan(State Key Laboratory of Water Resources and Hydropower Engineering Science,Wuhan University,Wuhan 430072,China)
出处
《人民黄河》
CAS
北大核心
2022年第4期57-62,共6页
Yellow River
基金
国家自然科学基金资助项目(51725902)
国家重点研发计划项目(2017YFC0405501)。
关键词
断面形态
洪水演进
数值模拟
游荡段
黄河下游
channel geometry
flood routing
numerical modelling
braided reach
Lower Yellow River
