中文摘要：

采用浑水控制方程，建立了基于耦合解法的一维非恒定非均匀沙数学模型，用于模拟高含沙洪水演进时的河床冲淤过程。然后采用黄河下游游荡段1977年7—8月实测高含沙洪水资料对该模型进行率定，基于水沙耦合解法的各水文断面流量、总含沙量及分组含沙量的计算过程与实测过程符合更好，计算的沿程最高水位及累计河段冲淤量与实测值也较为符合。最后还采用2004年8月高含沙洪水资料对该模型进行了验证。模型率定及验证计算结果表明，采用一维水沙耦合模型计算高含沙洪水过程，能取得较高的精度。

英文摘要：

Hyperconcentrated sediment-laden floods usually occur in the Lower Yellow River （LYR） during rainy seasons. During these floods, extreme high water levels and strong channel scour in local reaches often occur, which may cause the damage to the safety of flood control engineering. Therefore, it is necessary to adopt one-dimensional （1-D） morphodynamie models to simulate hyperconcentrated floods and corresponding channel evolution in the LYR. In the current study, a 1-D coupled morphodynamic model has been developed to simulate hyperconcentrated floods. In this model, the standard Saint-Venant equations are modified, and the sediment concentration and bed evolution terms are directly included in the modified equations. These equations are used together with the non-equilibrium transport equation for graded sediments and the equation of bed evolution. Since the governing equations are solved jointly, the hydrodynamic, sediment transport and morphological parameters are obtained simultaneously. The model was first applied to simulate a hyperconcentrated flood event occurring in 1977 in the LYR, with the field measured data of discharge, total and graded sediment concentrations at hydrometric sections being used to calibrate the model. It was then used to predict the discharge and sediment concentration hydrographs in the 2004 flood event, again using the field measured data to verify the model. Close agreement was obtained between the model predictions based on the coupled solution and the observed data.