灌区高含沙输水渠道淤积成因分析

渠道淤积是影响灌区高含沙输水渠道正常运行的一个关键问题，以新疆巴音沟河安集海一库引水副渠的淤积计算为例，根据泥沙起动速度与水流速度，推移质输沙率与水流挟沙力等理论计算结果，从不同角度分析了灌区高含沙输水渠道的淤积成因。理论计算结果表明：为了防止高含沙输水渠道的淤积，在渠道设计中不能只考虑水流速度大于起动速度；对于底坡沿程分段变化的高含沙输水渠道，设计应按最小坡度渠段校核其输沙能力，以保证渠道全程不发生淤积。为验证上述理论计算的准确性，开展了原型观测试验，结果表明：理论计算结果和实测结果符合较好，渠道淤积理论计算过程是合理和可靠的，可以为工程设计和管理单位提供重要参考。

Analysis of the cause for sediment deposition of high-silt conveyance channel in irrigation areas

Channel siltation is the key point which affects the working for the high-silt conveyance channel in irrigation area. This paper takes the siltation calculation of the secondary channel of An-Jihai reservoir in Xinjiang Ba-Yin river as an example. According to the theoretical calculation results of sediment threshold velocity and water flow velocity, sediment discharge of bed load and silt carrying capacity, the cause of silt deposition of high-silt laden conveyance channel was analyzed from different aspects. The results of theoretical calculation indicate that water flow velocity should not only be considered that it is greater than competent velocity in designing channel, its transport capacity should also be checked according to the minimal slope of channel when the slope of channel changes along the length to prevent channel from silting. To verify the accuracy of the above calculation, the prototype observation experiment was carried out. The results show that theoretical calculation result accords with prototype observation, and the theory calculation process of channel is rational and reliable, which can provide some important references for engineering design and management units.