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河道裁弯及三峡工程运用对荆江石首河段的河床演变产生了显著影响。结合实测水沙及地形资料分析,研究了该河段近50年来的河床演变特点,主要包括河床冲淤、平面及断面形态调整三个方面。分析结果表明:两次裁弯使得石首河段平面形态发生显著调整,1966-1975年该河段深泓平均摆幅达42.0m/a,且总体向左岸摆动。三峡工程运用后,大规模护岸工程的实施使石首河段的平面形态趋于稳定,深泓平均摆幅减小到29.8m/a,但北门口下段、调弦口弯道等位置的深泓摆动仍较为剧烈,使得这些局部河段岸线崩退现象十分明显。此外还分析了石首河段断面形态的调整过程,并建立了河段平滩河槽形态参数与前5年汛期平均水流冲刷强度的经验关系式,用于反映河段平滩河槽形态随水沙条件的变化趋势。
River bend and the use of the Three Gorges Project had a significant impact on the riverbed evolution in the Shishou section of Jingjiang River. Based on the analysis of measured sediment and sediment data, the characteristics of riverbed evolution over the past 50 years have been studied, including three aspects: river bed scouring and silting, plane and section shape adjustment. The analysis results show that the flat shape of the first section of Shishou River has been significantly adjusted by two cut-offs. From 1966 to 1975, the average swing amplitude of the deep reach reaches 42.0m / a in the reach of the river and the overall swing to the left bank. After the Three Gorges Project was put into operation, the implementation of large-scale revetment project stabilized the plane shape of Shishou reach, and the average swings of deep reach decreased to 29.8m / a. However, Hong swing is still more intense, making these partial river bank collapse phenomenon is very obvious. In addition, the adjustment process of the section shape of the Shishou River section was also analyzed, and the empirical relationship between the shape parameters of the Pingtan section of the river section and the mean current scour intensity in the flood season in the first 5 years was established, which was used to reflect the change of the shape of the Pingtan section along the water and sand Trend.