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三峡水库蓄水后,长江中游局部河段冲刷调整剧烈,尤以分汊河段最为显著,给航运及河势稳定带来了一系列不利影响。以荆江典型分汊河段——沙市河段为例,分析了三峡水库蓄水前后的演变特点,明确了水动力条件、来沙变化及洲滩相互作用对河床演变的重要影响,并提出了影响滩槽变化的特征流量级的概念。在此基础上,采用数学模型对河床演变的趋势进行预测,结果表明,该河段的滩槽格局将进一步调整,通航安全问题仍然存在。
After the impoundment of the Three Gorges Reservoir, the scouring of local rivers in the middle reaches of the Yangtze River has been drastically adjusted, especially in the Fenghuang reach, which has brought a series of unfavorable impacts on the stability of shipping and the river. Taking the typical Fenhe section of Shajing as an example, the evolution characteristics of the Three Gorges Reservoir before and after impounding are analyzed, and the important influence of hydrodynamic conditions, sediment change and bank-beach interaction on river bed evolution is clarified. The concept of characteristic flow level that affects beach trough changes. On this basis, the mathematical model is used to predict the trend of river bed evolution. The results show that the pattern of beach trough in this section will be further adjusted, and the navigation safety problem still exists.