摘要
以二十余年的观测资料为基础，对汉江丹江口水库下游河床调整过程中下伏卵石层的作用进行了系统的分析。在沙质河床中存在着下伏卵石层的情况下，卵石层的暴露是使河床下切受到抑制的决定性因素。随着卵石层的暴露，河床糙率将急剧增大，局部河床将不得不采取加大比降的方式进行补偿。当卵石层出露以后，河底抗冲性急剧增大，使得河岸相对于河底的抗冲性大大减小，因而可能出现展宽趋势。
Underlying gravel layers can be found in many large plain rivers.When the buried depth of the gravel layers are within the reach of down cutting of released clear water after reservoir construction, it would be exposed with the progress of channel erosion,and then exerts a far reaching influence on the channel adjustment. In Hanjiang River, the down cutting has been greatly reduced and then even stopped due to the totally coarsening of bed material composition. The exposure of gravel layer results in a dramatic increase in the bed's hydraulic roughness, so the channel slope may increase after a decline during the period when the gravel layer has not yet been exposed. Moreover, the exposed gravel layer increases the erosion resistance of bed material, thus, leading to a tendency towards channel widening.
出处
《泥沙研究》
CSCD
北大核心
1999年第3期48-52,共5页
Journal of Sediment Research
基金
中国科学院留学经费择优支持回国工作基金
国家自然科学基金
关键词
下伏卵石层
河床调整
汉江
丹江口水库
underlying gravel layer, downstream dam channel adjustment, channel down cutting, Hanjiang River
