三峡库区黄花城河段泥沙淤积情况的二维数值模拟

为准确反映三峡库区真实的泥沙淤积情况,以已有二维平面水沙模型为基础,考虑絮凝及床面泥沙固结后密度变化等因素,改进细沙冲淤判别标准,推导出泥沙运动及河床演变方程,将改进后的模型应用于三峡水库典型淤沙河段黄花城河段的泥沙冲淤变化模拟中,模型计算值与实测值对比结果表明,模型模拟精度较好,改进的泥沙模型可较真实地反映库区细沙的输移特性。在此基础上,利用该改进模型预测水库运行未来20年(2013~2032年)黄花城河段的演变趋势,发现主要淤积部位在左汊,且重点淤积部位逐渐向左汊出口转移,右汊淤积发展相对缓慢,该河段仍保持淤积状态,但整体淤积速率有所放缓。研究成果对于准确预判三峡库区的泥沙淤积状况意义重大。

Two-dimensional Numerical Simulation of Silt Deposition in Huanghuacheng Reach of the Three Gorges Reservoir Area

Based on the existing two-dimensional numerical simulation model, this paper considered the flocculation structures of fine sediment and the consolidation of the bed material to improve the discriminating standard of critical condition of erosion or deposition status, and derived the equations of sediment movement and riverbed deformation to reflect the real situation accurately. An improved model was applied to the research on Huanghuacheng reach river, and it was capable to simulate the change of sediment erosion and deposition. Through the numerical model, the evolution law of Huanghuacheng reach in the next 20 years was provided in this paper. The results show that the left branch of Huanghuacheng reach is still the main part where sediment deposition is severe, and the focus gradually transfers towards the outlet of the left branch. The deposition rate of the right branch is relatively slow. The deposition state of the reach would still remain, but the deposition rate would slow down until it is balanced. This research is significance for the accurate prediction of sediment deposition in the Three Gorges Reservoir Area.