摘要
针对李家岩水库下游消能防冲问题,通过1∶30水工模型试验对比了传统连续坎和新型燕尾型挑坎下游挑射水舌特性及河道冲刷形态。试验结果表明:燕尾型挑坎对上游来流的适应性好,起挑流量要求更小。燕尾坎体型下挑射水舌底缘偏离底板程度随单宽泄量的增加而增大,造成近端挑距越小。燕尾型挑坎相比连续坎水舌的横向扩散明显减弱,且沿水流方向充分拉伸,整个水舌落点范围呈狭长型,从而避免了对狭窄型水垫塘或河道两侧岸坡的冲刷,燕尾型挑坎更加适用于狭窄型河谷。燕尾坎体型下挑射水舌的落水范围总体相比连续坎得到伸展,有效减小了入水单宽流量,下游河道的水体波动及冲刷均有所减弱。在试验和类似工程的基础上总结得出了燕尾型挑坎的体型设计原则,相关研究成果可供其他工程参考。
Aiming at the problem of downstream energy dissipation and erosion control of Lijiayan Reservoir,the characteristics of the downstream water-jet nappes and river channel scouring patterns from both the conventional continuous flip bucket and new type of leak-floor flip bucket are compared through a 1 ∶ 30 hydraulic model experiment. The experiment result shows that the leak-floor flip bucket is more adaptable to the upstream inflow with a smaller discharge of starting ski-jump. Under the condition of leak-floor flip bucket,the degree of the deviation of the water-jet nappe bottom edge from the bottom slab is increased along with the increase of the discharge per unit width,which makes the near-end ski-jump distance smaller. Compared with the continuous flip bucket,the transverse diffusion of the water-jet nappe from the leak-floor flip bucket is obviously weakened and sufficiently stretches along the flow direction,while the entire range of the nappe falling point is long and narrow and avoids scouring the narrow plunge pool or both the river banks consequently,thus the leak-floor flip bucket is more suitable for narrow valley.Compared with the continuous flip bucket,the water-falling range of the jet-nappe from the leak-floor flip bucket is stretched,and then the unit discharge of inflow is effectively decreased,from which both water fluctuation and scouring of the downstream channel are weakened to some extent. The shape design principles and the related study results of the leak-floor flip bucket summarized in accordance with the relevant experiments and similar projects can provide references for the other projects concerned.
作者
程文磊
杨庆
昌子多
CHENG Wenlei;YANG Qing;CHANG Ziduo(State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, Sichuan, China;College of Water Resource and Hydropower, Sichuan University, Chengdu 610065, Sichuan, China)
出处
《水利水电技术》
CSCD
北大核心
2018年第4期63-69,共7页
Water Resources and Hydropower Engineering
基金
国家重点研发计划课题(2016YFC0401707)
关键词
燕尾型挑坎
挑射水舌
体型设计
leak-floor flip bucket
water-jet nappe
type design
