论文部分内容阅读
本文在概述了(1)汉江回水变动区河谷地貌特点及对河道形态的影响,(2)典型的山区河流来水来沙特性,(3)在蓄水后水库调度及淤积分布等三个问题的基础上,分析了建库后汉江干流回水变动区纵横剖面变化,再造床过程中河道形态的演变、年内的冲淤变化及河床地貌等四个方面的问题。由此初步归结出河床演变的几个特点:1.坝前水位的调度是回水变动区河床演变的控制性因素;2.堆积过程是河床演变的主导;3.河床显著细化,泥沙沿程分选强烈;4.库区弯曲狭窄、纵泓剧烈起伏的地质地貌条件对河床变形的影响显著;5.河床变形对水流的影响强烈,同时出现一些新的流态,6.回水变动区每年都经历“汛期淤积、枯季消落冲刷和汛初充水冲刷”的“一淤二冲”的变形过程。最后,简要地讨论了三峡水库库尾泥沙淤积的几个问题。
This paper summarizes (1) the valley landform features and the impact on the channel morphology of the Hanjiang backwater variation zone, (2) the typical features of incoming and outgoing water from mountain rivers, (3) the reservoir dispatch and siltation distribution after water storage On the basis of the analysis, the paper analyzes the vertical and horizontal cross-section changes of the backwater variation zone of the Hanjiang River after the reservoir was built, the evolution of the channel shape during the re-engineering of the riverbed, the scouring and silting changes during the year and the river bed landform. The characteristics of river bed evolution are summarized as follows: 1. The regulation of water level in front of dam is the controlling factor of river bed evolution in the backwater variation zone; 2. The accumulation process is the dominant factor of riverbed evolution; 3. The river bed is significantly refined, 4. The reservoir area is narrowly curved and the geological and geomorphic conditions of the vertical and horizontal fluctuations of the riverway have a significant impact on the riverbed deformation. 5. The riverbed deformation has a strong influence on the water flow and some new flow regimes occur at the same time. Every year, the changing area undergoes the deformation process of “one silt and two reds” in “siltation in flood season, scouring in dry season and scouring flood in early flood season”. Finally, a brief discussion of the Three Gorges Reservoir sediment deposition at the end of several issues.