河道生产堤对洪水影响的二维数值模拟研究

河道主槽两侧修建的生产堤影响滩槽泥沙横向交换,对河床演变带来很大影响。本文针对黄河下游游荡型河段的现实状况,采用平面二维水沙数学模型按现状生产堤、废除生产堤、限制生产堤三种条件进行了典型洪水的模拟,模拟计算给出了夹河滩-高村河段不同边界洪水演进、漫滩的过程及滩区淹没程度。作者分析了三种不同边界条件对洪水水位、河段流速、滩槽冲淤的影响,表明废除生产堤使洪水提前进滩,与现状生产堤状态相比大大降低了河道洪水位;限制生产堤方案可以适当控制漫滩流量,扩大滩槽泥沙横向交换,改善滩区生产条件。为了维持黄河河槽活力,协调人河关系,抑制二级悬河发展,限制下游河道生产堤治理方案是比较适宜的。

Influence of productive embankments on river flooding by 2-D Numerical simulation

The productive embankments on the watercourse bottomland disturb the water-sediment lateral exchange between bottomland and main flume,which have great influence on the riverbed evolution.In the light of the wandering reach in the lower yellow river,the typical flood with the 2-d water-sediments was simulated,with mathematical model basing on three designed riverbed(with embankments,without embankments,restricted embankments).The simulation result gives the flood evolution,the process of the overflowing the bottomland and the extent of the submerged bottomland with different boundaries in the Jiahetan-Gaocun reach.The author analyzed the influence of the flood level,the river flow velocity,the scouring and depositing of the bottomland and the flume under three different boundary conditions.The result shows that without embankments flood into the bottomland occurred significantly earlier,the flood level greatly reduced,comparing with the present embankments;and restricted embankments would suitably limit the discharge flow into the bottomland,enlarge sediment transfer from the main course to the bottomlands,improve the conditions of production.In the light of the long-term strategy of the sustaining dynamics of the flume and the suppression secondary suspended river,the restricted embankments is the considerable one for the improvement watercourse in the downstream.