三峡水库汛期排沙效率研究

Study on sediment transport efficiency of Three Gorges Reservoir during flood season

水库减淤调度是保障水库综合效益发挥的重要措施。以2003~2018年三峡库区主要水文站实测水沙数据为基础,统计分析了库区来水来沙规律,将库区按照沿程水文站布置分为3个库段,采用逐步回归的方法探讨了库区不同库段的输沙比与不同影响因素之间的相关情况,并建立了不同库段输沙比公式。结果表明:(1)寸滩至清溪场库段输沙比的主要影响因素为流量沿程变化系数和水沙系数,清溪场至万县库段输沙比的主要影响因素为洪水滞留系数和含沙量,万县至庙河库段输沙比的主要影响因素为洪水滞留系数和流量;(2)基于不同库段排沙比公式提出了提高排沙效率分段调度的新思路,即沙峰输移至清溪场站降低水位,输移至万县站继续加大下泄流量。研究成果可为三峡水库沙峰优化调度提供参考。

Reservoir sediment ejection regulation is an important measure to ensure the comprehensive benefits of reservoirs.Based on the measured data of water and sediment in the main hydrological stations of the Three Gorges Reservoir(TGR)from 2003 to 2018,this paper analyzed the law of water and sediment in the reservoir area.According to the layout of hydrological stations along the river,the reservoir area was divided into three sections,and the correlation between sediment transport ratio and different influencing factors in different sections was discussed by stepwise regression,and the formulas of sediment transport ratio in different reservoir sections were established.The results showed that:(1)the main influencing factors for sediment transport ratio from Cuntan to Qingxichang section were discharge variation coefficient and water-sediment coefficient,the main influencing factors for Qingxichang to Wanxian section were flood detention coefficient and sediment concentration,and the main influencing factors for Wanxian to Miaohe section were flood detention coefficient and discharge.(2)Based on the formula of sediment transport ratio of different reservoir sections,a new idea to improve the efficiency of sediment discharge was put forward,namely lowering the water level when the sand peak transporting to Qingxichang station,and continuing to increase the discharge when the sand peak transporting to Wanxian station.The research results can provide reference for the optimal operation of the Three Gorges Reservoir.