锦屏二级非常规洪水冲沙减淤优化调控研究

Optimizing regulation of Jinping Ⅱ reservoir to reduce sediment deposition using unconventional flood flushing

泥沙淤积严重会影响水库正常运行,但汛期畅泄冲沙又会造成一定发电损失。针对人工泄水冲沙解决水库泥沙淤积问题,设计了一种非常规洪水冲沙方式,通过物理模型试验研究了对称非常规洪水与非对称非常规洪水输沙规律。结果表明,对于对称非常规洪水,平均流量相等条件下,输沙能力随着流量变幅的增大而增大;对于非对称非常规洪水,平均流量与峰流流量不变条件下,输沙能力随基流时长与峰流时长比值的减小而增大。并基于此建立了锦屏二级三维水动力泥沙数值模拟模型,设计了合理的非常规洪水冲沙方式,验证了非常规洪水对锦屏二级库区泥沙输移效果的优化。非常规洪水冲沙方式对解决水库泥沙淤积,节约冲沙用水量,达到经济最优有一定参考意义。

Severe sediment deposition affects normal operation of reservoirs, but discharging flood water from them in flood season often causes a certain loss of power generation. Aiming at the problem of sediment deposition in reservoirs, this paper designs an unconventional flood-flushing method using reservoir regulation to flush away sediment during unconventional floods. Physical model tests are used to study the trends of sediment transport during symmetrical and asymmetric unconventional floods. Results show that under the symmetrical floods of a fixed average flow rate, the capacity of sediment transport is increased with the increasing flow amplitude, while under the asymmetric floods of fixed average and peak flow rates, it is increased with a decrease in the ratio of base flow duration to peak flow duration. Based on this, we develop a three-dimensional numerical model of hydrodynamics and sediment transport in the Jinping II reservoir, design a reasonable unconventional flood-flushing mode, and verify its effect on sediment flushing and deposition reduction. Thus, unconventional flood flushing is an effective method to reduce sediment deposition in reservoirs, helping save flushing water and achieving economic optimum.