弱爬振现象对平板闸门振动的影响研究

Study on influence of weak climbing vibration on plane gate vibration

本文基于巴塘水电站几何比尺为1:25的闸门水弹性模型,为研究闸门在动水闭门过程中可能出现的弱爬振现象,改变其上游水位使闸门产生微弱爬振,分析平面闸门下落过程中发生爬振前后门体不同部位局部应力、整体加速度和位移的变化,研究闸门微弱爬行振动特性。研究结果表明:(1)弱爬振不改变闸门原有的整体振动类型;弱爬振时闸门垂向振动加速度能量增加了2.6倍。(2)闸门垂向振动位移在弱爬振时约为无爬振的11倍,其均方差幅值已超出标准,属于严重振动,可能会对闸门及其连接结构产生不利影响。(3)弱爬振情况下,受影响最大的是吊耳正下方测点15#,闸门在高水头运行时有可能发生吊耳撕裂;应力主频增大约10倍,门体在微弱爬振的影响下,闸门局部受迫振动转变为周期性振动。因此,应该对闸门主纵梁上侧及吊耳等受爬振影响较大的部位进行加固强化,避免发生破坏。

This study examines the phenomenon of weak climbing vibration during hydrodynamic gate closing and its effect on gate vibration through an experiment on a 1:25-scale hydroelastic plane gate model for the Batang hydropower station.We control the weak gate vibrations by changing the upstream water stage,observe time variations in local stress at different locations of the gate and in its overall acceleration and displacement during gate closing after weak climbing vibration starts,and examine the characteristics of gate vibrations.The results show that 1)weak climbing vibration does not modify the overall vibration modes of the gate,though it can increase the energy of vertical vibration acceleration by 2.6 times.2)The gate’s vertical vibration displacement is about 11 times that of the non-climbing vibration case,with its mean square deviation amplitude beyond the standard,indicating a serious vibration that may produce adverse effects on the gate and its connection structures.3)Weak climbing vibration has the greatest effect on the measuring point No.15 located directly below the lifting lug and could tear the lug under high water head conditions.A roughly 10-time increase in the dominant frequency of stress can be observed at this point,and the local forced vibration of the gate switches to the state of periodic vibration.Thus,to avoid structure damage,it is necessary to strengthen the upper part of the main longitudinal beam of the gate and the lifting lug,which are both greatly affected by climbing vibration.