小挑坎对某拟建大型水电站导流洞出口区消能与冲刷改善机理研究  

Study on Mechanism of Energy Dissipation and Erosion Improvement of Diversion Tunnel Outlet Area by Small Flip Bucket

作　　者：赵昱东 刘进 李东杰 马旭东[1] ZHAO Yu-dong;LIU Jin;LI Dong-jie;MA Xu-dong(State Key Laboratory of Hydraulics and Mountain River Engineering,Sichuan University,Chengdu 610065,China;PowerChina Zhongnan Engineering Corporation Limited,Changsha 410019,China;PowerChina Huadong Engineering Corporation Limited,Hangzhou 311122,China)

机构地区：[1]四川大学水力学与山区河流开发保护国家重点实验室,四川成都610065 [2]中国电建集团中南勘测设计研究院有限公司,湖南长沙410019 [3]中国电建集团华东勘测设计研究院有限公司,浙江杭州311122

出　　处：《水电能源科学》2023年第5期101-104,92,共5页Water Resources and Power

基　　金：国家自然科学基金项目(51809187)。

摘　　要：山区河道导流隧洞出口区具有单宽流量大、流速高、河床覆盖层深且抗冲流速小等特点,多数隧洞出口区河床冲刷剧烈,而布置大型消能措施较困难,故提出在隧洞出口布置小挑坎的措施。在物理模型试验观测隧洞出口区水流流态和河床冲刷的基础上,采用数值模拟方法计算导流隧洞出口区水流流场,研究河床冲刷改善的内在机理。结果表明,导流洞出口增设小挑坎后,可增大出洞高速水流的横向扩散和减小单宽流量,增加局部消能率,从而降低河道岸边流速;高流速出洞水体占比明显减少,使高速水流无法直冲右岸滑坡体,减小滑坡体范围流速;出洞水流宽度增加,出洞水流方向变为斜向上出流,减弱对右岸滑坡体的冲击,并且使导流洞出口区及下游河道受到的冲刷明显减弱。研究成果可为工程实践提供参考。The outlet area of river diversion tunnel in mountainous areas is characterized by large discharge per unit width,high flow velocity,deep riverbed overburden and low anti-scour flow velocity.The river bed at the outlet of the tunnel is severely scoured,and it is difficult to arrange large energy dissipation measures,so it is proposed to arrange small flip bucket at the outlet of the tunnel.On the basis of the physical model test to observe the flow pattern and river bed scouring in the outlet area of the tunnel,the numerical simulation method is used to calculate the flow field in the outlet area of the diversion tunnel,and the internal mechanism of the improvement of river bed scouring is studied.The results show that after adding a small flip bucket at the outlet of the diversion tunnel can increase the lateral diffusion of the high-speed flow out of the tunnel,reduce the unit width discharge,increase the local energy dissipation rate,and thus reduce the velocity of the river bank.The proportion of water body coming out of the tunnel with high flow velocity is obviously reduced,which makes the high-speed water flow unable to directly rush the landslide mass on the right bank,and reduces the flow velocity within the landslide mass.The width of water flow out of the tunnel increases,and the direction of water flow out of the tunnel becomes inclined upward,which weakens the impact on the landslide on the right bank,and significantly weakens the scouring of the outlet area of the diversion tunnel and the downstream river channel.This study can provide reference for engineering practice.

关 键 词：模型试验 导流隧洞 挑流坎 数值模拟 

分 类 号：TV653.3[水利工程—水利水电工程]