| 摘要: |
| 某水利枢纽位于西江干流浔江下游河段，枢纽坝轴线跨两岛三江，分三期导流，三期中江截流截断中江天然河槽，江水通过外江泄洪闸下泄，截流标准为相应时段5年一遇平均流量，截流设计流量2 030 m3/s。实施截流时，由于外江上游围堰拆除不到位及船闸导航设施影响，外江实际分流能力远小于设计预期；又受到珠江补淡压咸调水控制流量不小于1 800 m3/s的限制，截流进占速度受限，截流历时延长；龙口河床2 m厚覆盖层全被冲刷，右侧裹头受淘刷，坡脚护脚钢筋铅丝笼全部坍塌，护坡钢筋铅丝笼裹头下沉，截流戗堤堤顶出现裂缝；进占缓慢使得中江下游河道退水明显，龙口下游水位低于设计下游水位2 m，龙口最终落差远大于设计值（达4.09 m），施工难度及风险加大。文章具体分析了截流难度增加的原因，梳理了应对措施，总结了最终成功截流的经验，为今后类似工程制定截流方案与实施提供借鉴。 |
| 关键词: 水利枢纽 龙口 截流 |
| DOI： |
| 分类号:TV551.2 |
| 基金项目: |
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| Analysis of river closure construction difficulties for a hydroproject |
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XI Hao1,2
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1.Xi′an University of Technology;2.Sinohydro Engineering Bureau No.4 Co., Ltd.
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| Abstract: |
| A hydroproject is located at the lower reaches of the Xunjiang River, the main stream of the Xijiang River system, of which the dam axis crosses two islands and three channels, with diversion in three phases, and three times of the river closure cutting off the natural channel in the river, and the river flow flowing through the outer river sluice. An average discharge of the return period of once in 5 years is taken as the discharge standard of the middle river closure at the third stage, the corresponding design discharge for river closure is 2 030 m3/s. When implementing river closure, because the removal of the outer river upstream cofferdam is not in place and there is a disturbance caused by the guide facilities for ship lock navigation, the actual river diversion capacity of the outer river is far smaller than the design expectations, but is also influenced by water transfer requirements of the Pearl River with supplementing freshwater to suppress salty water, and controlling the flow of not less than 1 800 m3/s. The advancing speed of the river closure is limited, and the river closure time lasts longer. 2 m-thick cover layer on the riverbed is washed away, the advancing front on the right side is scoured, the reinforcing cage for protecting slope toe is collapsed, the advancing front of the reinforcing cage goes down, and cracks on the berm top appear. Too slow river closure results in falling water in the downstream of the middle river, and the downstream of the closure gap water level is lower than the design downstream water level by 2 m. And the final fall along the closure gap is twice more than the design fall, reaching 4.09 m, and construction difficulties and risks are finally increasing. A detailed analysis of river closure difficulties is made in this paper, and the solution measures are presented. The summation of the experience of the ultimate success for the river closure can provide a reference for future similar projects in the planning and implementation of the river closure. |
| Key words: hydroproject closure gap engineering river closure construction |
