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本文通过进行不同地震动输入的振动台模型试验,研究模型坝的动力特性及其变化规律,并通过土石坝振动台模型试验相似率推算了原型坝的动力特性。研究表明:(1)对于一次振动,模型坝各测点所得自振频率及阻尼比基本一致,表明坝体具有大致固定的振型;(2)随台面激励峰值加速度的增大,自振频率明显降低,而阻尼比增大;(3)自振频率及阻尼比均与先期振动历史密切相关,先期振动使坝体自振频率减少,阻尼比增大,先期振动的影响与先期振动的强度有关;(4)蓄水对模型坝的自振频率有明显影响,坝体自振频率在满库时明显比空库时低。
In this paper, the dynamic characteristics of the model dam and its variation are studied through shaking table model tests with different ground motion inputs. The dynamic characteristics of the prototype dam are calculated by the similarity of the model test of shaking table of earth-rock dam. The results show that: (1) For a single vibration, the natural frequencies and damping ratios obtained at each measuring point are basically the same, indicating that the dam body has a substantially fixed vibration mode. (2) With the increase of peak acceleration, the natural frequency (3) Both natural frequency and damping ratio are closely related to the previous vibration history. Pre-vibration reduces the natural frequency and damped ratio of the dam, and the influence of the pre-vibration and the pre-vibration intensity (4) The impoundment of water has a significant effect on the natural frequency of the dam, and the natural frequency of the dam is obviously lower than that of the empty reservoir when it is full.