# Characteristics of Plane Gate Vibration and Holding Force in Closing Process by Experiments
## 4 Conclusions  
Physical model test was used to investigate the characteristics of gate vibration and holding force in a plane gate at two operation modes. More attention was paid to the gate vertical vibration and the correlation between the gate vibration and holding force. The results are as follows.  
The vibration acceleration is significant in lateral and horizontal directions, and it is 10 times higher in the vertical direction in fixed gate opening. In closing process, however, vertical vibration is stronger than those in the lateral and horizontal directions. Dominant frequency of vertical vibration gradually decreases from 14 to 7 Hz in a step form. The experiment results also show that gate vertical vibration simplified into single degree of freedom is reasonable through equivalent stiffness theory.  
At the same gate opening, the holding force in closing process is less than the fixed gate opening. The horizontal panel thrust of plane gate can be treated as a hydraulic factor for the crawl vibration. Once the panel thrust exceeds the critical threshold, crawl vibration happens. After the crawl vibration, the gate stops motion at a certain distance from the chamber floor and the failure of gate-closing happens. The higher is the upstream water level, the greater is the distance. Increasing the vertical downward loads by modified shape of gate bottom edge can solve the failure of gate closing. More attention should be paid to the holding force to prevent the large fluctuation value from exceeding hoists capacity and tearing failure.  
For fixed gate opening, gate vibration has almost no influence on holding force and can be ignored in determining the hoists capacity. In closing process, however, absolute value of correlation coefficient in three directions is relatively high. Holding force is significantly positively correlated with the vertical vibration and is significantly negatively correlated with lateral and horizontal vibrations. Thus, the gate vibration effect on the holding force should be considered in determining the hoists capacity under closing process.  
Conceptualization, Y.W. and G.X.; methodology, Y.W. and G.X.; investigation, Y.W.; data curation, W.L.; writing--original draft preparation, W.L.; writing--review and editing, F.L. and Y.D.; visualization, Y.W.; and supervision, G.X. All authors have read and agreed to the published version of the manuscript.  
This research was funded by National Natural Science Foundation of China (Grant No. 51779166).  
The authors gratefully acknowledge the editors and anonymous reviewers for their insightful and professional comments, which greatly improved this manuscript.  
The authors declare no conflict of interest.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Water Depth (m)**} & \multicolumn{3}{c}{**Initial Stage**} & \multicolumn{3}{c}{**Transitional Stage**} & \multicolumn{3}{c}{**Crawl Stage**} \\ \cline{2-10}  & **Lateral** & **Vertical** & **Horizontal** & **Lateral** & **Vertical** & **Horizontal** & **Lateral** & **Vertical** & **Horizontal** \\ \hline
16 & 0.045 ** & 0.418 ** & 0.021 & \(-\)0.472 ** & 0.946 ** & \(-\)0.644 ** & \(-\)0.724 ** & 0.737 ** & \(-\)0.644 ** \\
18 & \(-\)0.227 ** & 0.761 ** & \(-\)0.374 ** & \(-\)0.566 ** & 0.955 ** & \(-\)0.874 ** & \(-\)0.731 ** & 0.723 ** & \(-\)0.650 ** \\
20 & 0.271 ** & 0.285 ** & \(-\)0.032 & \(-\)0.555 ** & 0.941 ** & \(-\)0.678 ** & \(-\)0.720 ** & 0.732 ** & \(-\)0.664 ** \\
23 & \(-\)0.138 ** & 0.389 ** & \(-\)0.041 ** & \(-\)0.667 ** & 0.936 ** & \(-\)0.862 ** & \(-\)0.720 ** & 0.741 ** & \(-\)0.698 ** \\ \hline \hline \end{tabular} Note: * denotes a significant difference (\(p<0.05\)), ** denotes a significant difference (\(p<0.01\)).  
\end{table}
Table 5: Correlation between gate vibration and holding force in closing process.