官地水垫塘底板泄洪振动响应特性研究

Research on Sluice Vibration Response Characteristics of Slabs in Plunge Pool of Guandi Hydropower Station

利用官地水垫塘底板泄洪振动响应原型观测成果,分析了不同泄洪工况下底板振动强度的分布特征,同时应用现代谱分析方法,从频域的角度分析了底板泄洪振动的频域特征,并研究了不同泄洪工况及流量对底板振动特性的影响,以及各测点的相关性。结果表明,在官地水电站底流消能的情况下,位于消力池内前段(坝前0+149m)这一区域的板块振动响应最为剧烈,之后沿程减弱。水流的不对称流动和摆动,引起底板不同区域的板块振动强度分布规律产生显著差别。正常运行下的水垫塘底板是在水流荷载作用下的随机受迫振动,各测点的振动相关性较好,底板整体性也较好,且优势频率非常稳定地分布在0.6～1.7Hz之间。水垫塘内涡旋尺度较大,底板振动本身有着很好的相似性和明显的同步性。随着泄洪流量的增大,正常运行下的底板振动强度平稳增强,优势频率缓慢下降,且当泄流量高于1 500m3/s后,优势频率随泄流量增大而下降的速度趋于缓慢,并最终趋于稳定。

Based on the prototype observation results of the vibration response of plunge pool slabs in the Guandi hydropower station, the distribution of vibration strength of slabs had been analyzed under different spillway conditions. Meanwhile, the frequency domain characteristics of the sluice vibration of slabs were analyzed from the aspect of frequency domain using the modern spectral analysis method, and the effects of different sluice conditions and flow discharges on the vibration characteristics of slabs in plunge pool were studied. The correlation between different measuring points was also analyzed. The results showed that the most intensive vibration response is located in the forepart （0＋149 m） of the power consumption pond under the conditions of underflow energy dissipation in the Guandi hydropower station and the vibration response decreases along the way.The asymmetrical water flow caused different vibration strength distributions in different areas of the slabs. The slabs in the plunge pool vibrated randomly forced by the water flow load under the normal operation. The correlation between each measuring point was remarkable and the dominant frequency was stably distributed between 0.6 and 1.7 Hz. The scale of vortex was very large in the plunge pool and thus the vibration of slabs had good similarity and synchronicity. With the increasing of flow discharge, the vibration strength of the slabs increased as well under the normal operation while the dominant frequency decreased stably. When the flow discharge was more than 1 500 m3/s, the decreasing rate of dominant frequency tended to be slow and eventually stayed stable.