水口坝下水位治理工程施工期通航水流条件研究

Study on navigation flow condition in construction period of re-adjusting project for controlling water level below Shuikou hydropower station on Minjiang river

水口坝下水位治理工程施工导流阶段,因围堰导致河道过流宽度缩窄,容易出现大流速、漩涡、剪刀水、跌水等不良水流流态。为改善通航水流条件,进行了整体水工模型试验研究。根据水力学基本原理,通过采取圆弧连接上游纵横围堰、降低缩窄河道河床底高程等工程措施,消除了漩涡与跌水现象,减弱了剪刀水流强度,改善了水流条件。模型试验结果显示:工程措施实施后施工河段的最高安全通航流量模型观测值由Q=1 686 m3/s提高至Q=2 810 m3/s。

In the construction period of the re-adjusting project for controlling water level below Shuikou hydro-power station on Minjiang river, a series of bad flow patterns such as high velocity, eddy, scissor-like current and hy-draulic drop are easily appeared in one side of the watercourse due to the construction cofferdam on the other side.To improve the navigation flow condition in the watercourse, the overall hydraulic model test was carried out. Basedon cardinal principle of hydraulics, the engineering measures, such as using arc connection between upstream verti-cal and horizontal cofferdam, reducing riverbed elevation of the watercourse for diversion, have been adopted toeliminate the phenomenon of eddy and hydraulic drop, to weak the scissor-like current intensity and to improve theflow conditions. The result of model test shows model observations of the maximum safety navigable discharge in thewatercourse for diversion can increase from 1 686 m3/s to 2 810 m3/s after engineering measures.