泥沙研究

水库异重流总是处于超饱和输沙状态，在有效悬浮功作用下异重流可实现长距离输移，但有效悬浮功临界条件下的异重流运动特性尚未揭示。以泥沙达到有效悬浮功临界条件下的异重流运动特性为研究对象，建立异重流积深方程，利用异重流自相似理论分析平衡状态下的异重流运动特征。研究结果表明：在临界自悬浮状态下，床沙挟带系数随着粒径增大、坡降减小及阻力增大而增大；平衡状态下Richardson数随着阻力增加、坡降减小而增加，清浑水掺混系数随着Richardson的增大而降低。利用有效悬浮功分析了小浪底水库异重流运动过程，即随着异重流向坝前运动，有效悬浮功逐渐减弱。多沙河流水库实现异重流高效排沙，应使有效悬浮功小于零，即构建适当的水库底坡并减小异重流粒径。研究成果可为多沙河流水库减淤与保持有效库容提供理论基础。

Sediment transported by the turbidity currents in reservoirs are always in a state of over-saturation. Under the influence of sediment effective suspension power, turbidity currents can achieve long-distance transport. However, the movement characteristics of turbidity currents under the critical conditions of sediment effective suspension power have not yet been revealed. This study focuses on the movement characteristics of turbidity currents under the critical state conditions of sediment effective suspension power. Turbidity currents control equations are established, and the self-similarity theory of turbidity currents is used to analyze their movement characteristics in equilibrium. The results show that in the critical self-suspension state, the sediment entrainment coefficient increases with the increase in grain size, the decrease in slope, and the increase in resistance. In equilibrium, the Richardson number increases with the increase in resistance and the decrease in slope, while the mixing coefficient of clear and turbid water decreases with the increase in the Richardson number. The sediment effective suspension power was also used to analyze the movement of the turbidity currents in the Xiaolangdi Reservoir. It is found that the sediment effective power weakens when the turbidity current moves downstream. To achieve efficient sediment discharge in reservoirs, the sediment effective power should be less than zero, which means an appropriate reservoir bottom slope and finer grain size in the turbidity current is necessary to be constructed, which can provide a theoretical basis for sedimentation reduction and maintaining effective reservoir capacity in sediment-laden rivers.