三峡库尾卵石推移质输移对航道的影响

长江经济带建设发展迫切需要三峡库尾航道等级由3. 5 m提升至4. 5 m,而库尾推移质运动是必须解决的泥沙问题。采用三峡库尾航道水沙二维数学模型,根据2009—2016年三峡入库水沙资料,模拟变动回水区重庆至涪陵段推移质运动过程,将其冲淤分布及断面输沙量与实测资料对比,验证该数值模型的可靠性。以此为基础,预测30 a后三峡库尾航道推移质冲淤趋势,分析重点滩段航道内推移质冲淤分布、幅度以及输沙带特性,揭示推移质输移对航道的影响。该研究结果可为三峡库尾重庆至涪陵段4. 5 m航道等级提升建设的方案设计提供数据与技术支撑。

Impact of gravel bed load behavior on channel condition in fluctuating backwater zone of the Three Gorges Reservoir

The navigation condition of the fluctuating backwater zone of the Three Gorges Reservoir should improve its level from 3.5 m to 4.5 m in order to meet the development requirement of the Yangtze River economic belt,and the bed load transport at the reservoir head is the problem must be dealt with.Based on the 2D hydrodynamic-sediment transport numerical model for the Three Gorges Reservoir,the deposition and scouring process of the river reach from Chongqing to Fuling was simulated according to the water discharge and water level record from 2009 to 2016.The results were in good agreement with the field measurements for the sedimentation distribution and gravel bed load transport rate at from Chongqing to Fuling,illustrating the capability of the two-dimensional model to predict the bed load transport process in the Three Gorges Reservoir.The 2D numerical model was then applied to predict the change trend of the river reach in the next 30 years and analyze the distribution of the sedimentation,the density of the gravel bedload transport and its characteristics to investigate the influence of the gravel bed load behavior on the navigation condition in the key river reach.The results can provide technological support for the 4.5 m level waterway regulation in the fluctuating backwater zone in the Three Gorges Reservoir.