Analysis on the Vibration Characteristics of Ship Lift under Xiangjiaba Flood Discharge

Abstract

Xiangjiaba ship lift is adjacent to the powerhouse behind the dam on the left bank. During daily operation, it is affected by the operation of the left bank unit and the dam flood discharge during flood discharge, resulting in obvious vibration response in the ship lift area. Xiangjiaba hydropower plant arranges vibration monitoring points at typical parts of ship lift area to study the vibration influence of ship lift area. In this paper, the vibration response data obtained from monitoring are used for analysis and research. It is found that the excellent frequency band of pressure pulsation excitation generated by flood discharge to Xiangjiaba in flood season is 0.3 ~ 11 Hz, which presents the characteristics of narrow-band random vibration. The analysis shows that the flood discharge excitation to Xiangjiaba in flood season does not affect the safety of ship lift tower column structure; through modal analysis, the first and second natural frequencies of the tower structure are 0.94 Hz and 1.04 Hz, and the vibration mode is mainly reflected in horizontal shaking in the cross river direction; the third and fourth order natural frequencies are 2.52 Hz and 2.87 Hz, which are mainly reflected in the horizontal shaking of the tower structure along the river. The main frequency of flood discharge pressure pulsation excitation energy is mainly distributed in the low-frequency band, which can stimulate the first few low-frequency vibrations of Xiangjiaba tower column structure. Therefore, the tower column structure will produce obvious horizontal vibration response during flood discharge.