断波及其在上荆江河段传播特性研究

三峡水库投入运行后,其下游荆江河段洪水传播特性发生了一系列变化,主要表现为洪水传播时间明显缩短。通过建立荆江河段水力学模型,对比分析不同类型洪水波的水力要素,模拟分析水库不同泄流条件时洪水波传播特性,揭示了水库调度对洪水波的影响规律。研究表明:洪水在荆江河段传播时间缩短的主要原因是洪水波波型的改变;当三峡水库下泄流量在较短时间内出现较大变化时,洪水波在荆江河段不同范围、不同程度地表现为断波特性;相同条件时,断波流量越大、维持时间越长,以断波特性向下游演进的距离越远,洪水传播时间缩短现象越明显。

Surge wave and its propagation in upper Jingjiang Reach

Since the operation of Three Gorges Reservoir (TGR), the flood propagation characteristics in upper Jingjiang Reach changed significantly, especially the flood propagation time was much shorter. Based on hydraulic model of the river reach, the hydraulic parameters of different flood waves were studied and its flood propagation characteristics were analyzed under different TGR discharge conditions, and the influence of reservoir operation on flood wave was revealed. The results showed that the main cause for the shortening of flood propagation time was the change of flood wave shape in Jingjiang Reach.When the discharge of TGR changed greatly in a relatively short period, the flood wave in Jingjiang reach represented as surge waves in different reaches and degrees. Under the same conditions, the larger flow and the longer duration of surge wave is, the further propagation distance to the downstream as well as the more obvious phenomenon of shortening of surge wave is. 