黄河下游游荡河段河床演变对河道整治的响应

River bed changes in response to the river regulation at the wandering-braided reach of the lower Yellow River

为预测黄河下游游荡性河道大规模整治后对河床演变的作用,基于河流动力学理论,通过物理模型试验的方法,以黄河下游游荡性河道典型河段为对象,研究了河床过程对河道整治的复杂响应关系。研究结果表明,河槽横断面形态的调整与人工边界约束程度、流量变差及含沙量变差有关;只要整治工程体系平面布设合理,整治工程量达到一定规模后,通过河道整治,可使河槽横断面形态趋于窄深方向发展,促使游荡型河道向限制性弯曲型河道转化,同时,河道泄洪输沙能力有所提高;河道整治后,不同河段的比降调整不会平行进行。

In order to predict the effect of the river improvement on the channel evolvement at the wandering-braided reach of the lower Yellow River, based on the theory of fluvial dynamics, the complex ersponse of the channel changes to the river improvement at the wandering-braided reach of the lower Yellow River is studied by the physical model experiment.The results show that the regulation of channel section is related to the restrainted degree of man-made boundary, flow variation and sediment concentration.When the plan layout of regulation project system is reasonable and the quantity is enough, the channel section will be developed to a narrow and deep channel by river improvement, which will make the wandering-braided reach into a restricted tortuous channel.Meanwhile, the flood carrying capacity and sediment transport competency are increased.The regulation of fall at different reach doedn′t develop parallelly after the river improvement.