琼中抽水蓄能电站地下厂房结构振动特性分析

结合琼中抽水蓄能电站地下厂房实际情况建立了三维有限元模型,提取结构的模态分析了厂房结构的自振特性,基于谐响应法分析了地下厂房结构在各种工况机组动荷载作用和脉动压力作用下的动力响应,并根据国内相关文献及国外的相关标准提出了适用于琼中抽水蓄能电站地下厂房的振动控制标准。研究结果表明,合理选择围岩与厂房的连接形式,能够有效地优化结构整体动力特性;在机组振动荷载作用下机墩和楼板结构的振动响应较大,但机墩和楼板结构的振幅、振动速度和振动加速度等均在允许范围内;在额定出力条件下运行时,无翼区和转轮出口管附近区域的脉动压力,即优势频率为56.25 Hz对应的脉动压力是影响地下厂房楼板、立柱、风罩等结构振动的主要部分。

Analysis on structural vibration characteristics of underground powerhouse of Qiongzhong Pumped Storage Hydropower Station

In accordance with the actual status of the underground powerhouse of Qiongzhong Pumped Storage Hydropower Station，a 3-D finite element model is established herein，and then the self-vibration characteristics of the structure of the powerhouse is analyzed by extracting its structural modes. Based on the harmonic response analysis method，the dynamic responses of the structure of the underground powerhouse under the effects of both the dynamic load and fluctuating pressure of the pumping-generating units under all the operation conditions are analyzed，while the vibration control standard for the underground powerhouse of Qiongzhong Pumped Storage Hydropower Station is put forward according to the relevant domestic literatures and foreign standards. The study result shows that the overall dynamic characteristics of structures can be effectively optimized by reasonably selecting the mode of the joint between the surrounding rock and the powerhouse. Under the effect of the vibration load of the pumping-generating unit，the vibration responses from the structures of both the pedestal and the floor are larger，but the vibration amplitude，vibration speed and acceleration of therein are all within the allowable range. During the operation under the condition of the rated output，the fluctuating pressures in the area between wicket gate and runner and near the runner outlet tube，i.e. the fluctuating pressure corresponding to a dominant frequency of 56.25 Hz，are the main factors to impact the vibrations of the structures of floor，column，ventilation hood of the powerhouse.