环境激励下二滩拱坝拍振机理的研究

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振动与冲击 ›› 2012, Vol. 31 ›› Issue (3) : 1-7.

论文

环境激励下二滩拱坝拍振机理的研究

练继建1, 李成业1, 刘昉1, 宋明富2

作者信息 +

beat vibration of ertan arch dam under ambient excitation

Lian Ji-jian1, Li Cheng-ye1, Liu Fang1, Song Ming-fu2

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摘要

在二滩拱坝泄洪振动时程曲线中，可以看到波形的包络线随时间增大或减小的现象，波形非常像振动中的“拍”现象。通过对原型观测数据的分析，研究二滩拱坝拍振机理。首先引入自然界中“拍”的概念，论述了初相差、频率比和振幅比对“拍”的影响以及多列波合成拍的特性；然后应用随机子空间方法(SSI)和频谱分析方法，对二滩拱坝的模态参数进行识别；最后结合实测拍振现象的自身特点，对泄洪激励下二滩拱坝拍振现象的机理进行研究。结果表明，拱坝工作频率相近的前两阶振型振动是形成拍振的主要原因，此外，一个频带在1.27~1.39Hz的振动分量也参与了拍的合成，初步认为这一分量是由坝段间接触非线性引起的。

Abstract

Researching on the vibration time interval curve of Ertan arch dam under flood discharge excitation, we can see the phenomenon that the wave envelope increases or reduces along with the time. Firstly, the effects caused by initial phase difference, frequency ratio and amplitude ratio have been discussed. Secondly, dominant frequency of measured data has been collated and analyzed with the Auto Regressive Modal, obtaining the first four vibration mode based on SSI. Lastly, combined with special features of beat vibrations itself, beat vibrations of Ertan arch dam under discharge flow has been researched. The result shows that the main cause forming beat vibration is the former two orders vibration mode whose frequency is similar. In addition, a vibration component whose frequency band is during 1.27~1.39Hz also gives rise to forming “beat”. The component is considered at present that it is caused by nonlinear contact between dam sections.

导出引用

练继建;李成业;刘昉;宋明富. 环境激励下二滩拱坝拍振机理的研究[J]. 振动与冲击, 2012, 31(3): 1-7

Lian Ji-jian;Li Cheng-ye;Liu Fang;Song Ming-fu. beat vibration of ertan arch dam under ambient excitation[J]. Journal of Vibration and Shock, 2012, 31(3): 1-7