| 摘要: |
| 【目的】在考虑下游龙羊峡水库回水影响条件下，研究河床疏挖前后拟建的羊曲水电站中坝址厂房尾水特征断面的水位 流量关系，寻求提高有效发电水头的方法。【方法】采用预测 校正求解方法，应用一维河床冲淤变形计算模型，在不考虑龙羊峡水库回水时，对尾水河道2个开挖方案进行数值分析，分别考虑疏挖比降为0.000 5,0.001,0.001 5，疏挖宽度为50,80,140 m时的疏挖效果。通过多方案比较，确定推荐方案后，在考虑下游龙羊峡水库不同回水影响时，采用推荐尾水疏挖方案，研究龙羊峡水库回水影响下的羊曲水电站尾水疏挖效果。【结果】从疏挖工程量和电站尾水断面所获得的水头综合考虑，推荐疏挖比降为0.000 5，疏挖宽度为50 m的开挖方案，该方案在平均流量625 m3/s时，电站厂房尾水位比河道开挖前降低了5.15 m。经多条水位 流量关系曲线套绘分析发现，龙羊峡水库坝前水位超过2 596 m时，河道疏挖后羊曲水电站尾水位没有降低；龙羊峡水位低于2 596 m时，平均流量625 m3/s下，河道开挖后仍能获得不同程度的发电水头。【结论】羊曲水电站尾水河段具备河道疏挖疏浚的客观条件，在考虑龙羊峡水库回水影响下，推荐疏挖方案当河道平均流量625 m3/s时，在不同的回水高程条件下，羊曲水电站尾水水位降幅为0.48～4.47 m，所得计算结果可供水能规划部门参考应用。 |
| 关键词: 水电站 尾水疏挖 下游水库回水 水面线计算 水位 流量关系曲线 |
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| 基金项目:国家自然科学基金重点项目(40335050)；2009年高等学校博士学科点专项科研基金项目（20090204110019）；西北农林科技大学留学归国人员科研基金项目（01140507）；西北农林科技大学科研专项基金项目（A213020503） |
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| Study on tailrace dredging of hydropower station under considering backwater effects of Longyangxia reservoir |
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| Abstract: |
| 【Objective】Considering the impact of downstream backwater Longyangxia reservoir conditions,a scientific and reliable basis which enhances effective water head was provided to water planning and design department by comparisons of the cross section relationship between water level and water flow of hydropower station before and after the changing in tailrace dredging.【Method】By using Predictor Corrector method,dredging effects were focused on the combination of 2 different types on dredging the length of the program by using application of one dimensional deformation of riverbed erosion and deposition calculation model with different slope with 0.000 5,0.001,0.001 5 and different width with 50,80,140 m without considering the backwater effects of the Longyangxia reservoir.The recommended program was chosen by studying the effects of tailrace dredging of Yangqu hydropower station under considering the backwater effects of the Longyangxia reservoir.【Result】The recommended program was chosen by the amount of dredging works,power station tailrace section obtained after the head and dredging silt brought the issue into account,a slope dropped to 0.000 5,width of 50 m of the dredging program was recommended from dredging program Ⅱ,powerplant tailrace water level was 5.15 m lower than the natural riverbed encountering the average flow of 625 m3/s.A law of water level was found after several water level and flow rate curve drawn analysis,which suggested the river dredging tail water level wasn’t reduced when the water level of Longyangxia dam was higher than 2 596 m,the river dredging tail water level began to decline when the water level of Longyangxia dam was lower than 2 596 m.【Conclusion】The riverbed of Yangqu hydropower station could be dredged because it has objective conditions of dredging.Considering the influence of Longyangxia reservoir backwater recommended dredging program,the tailrace water level drops to 0.48-4.47 m with an average flow of 625 m3/s when the water level in the Longyangxia reservoir dam is different.The conclusion could be used as a program comparison by water planning and design department. |
| Key words: hydropower station tailrace dredging backwater of downstream reservoir water surface calculation relationship between water level and water flow |
