小浪底水库异重流高效输沙理论与调控

小浪底水库高效排沙是延长水库寿命的关键。水库在蓄水状态下,高效输沙主要体现在提高异重流排沙比与减少异重流滞留层淤积等方面。本文采用理论探讨、水槽试验及实测资料分析方法,研究水库输沙流态动态转换与异重流输沙水动力机制、水库滞留层物理参量变化及其与水动力之间的响应机制。提出了引入压力与动量修正系数的异重流动量方程与描述复杂流态下异重流潜入点判别公式;建立了异重流支流倒回灌淤积计算公式与支流拦门沙高程抬升值和支流淤积量的多元响应关系;明晰了异重流滞留层对后续洪水的响应关系,进而提出水库高效排沙调度原则。

Theory and regulation of sediment turbidity current venting with high efficiency in Xiaolangdi Reservoir

Efficient sediment releasing is the key operation to prolong the project life for the Xiaolangdi Reservoir. Under the condition of impoundment, high release efficiency can be achieved by increasing the ratio of output to input sediment load during turbidity current events and reducing the deposition from the stagnant layers created by turbidity currents. Combining the methods of theoretical study, flume experiments and field data analyses, this paper investigates the dynamic conversion between different flow regimes for sediment transport in reservoirs, the hydrodynamics for sediment transport of turbidity currents, the varia-tions in physical parameters of the stagnant layers and their response to flow conditions. A momentum equa-tion for turbidity currents was proposed, with the correction factors of pressure and momentum being includ-ed, and a plunge criterion was derived for turbidity currents under complex flow conditions. Moreover, the formulas were proposed for calculating the velocity and discharge of turbidity currents intruding the tributar-ies, and multiple regression analyses were conducted for the estuary sandbar elevation and deposition vol-ume of the tributaries. The responsive characteristics of the stagnant layers to subsequent floods were investi-gated. Finally, the operation principles for efficient sediment releasing were also provided.