拱坝振动台模型边界与材料特性对坝体自振特性的影响分析

Analysis of the influence of arch dam shaking table model boundary and material characteristics on the natural vibration characteristics of the dam

为了分析模型边界与模型材料对大型拱坝振动台试验模型坝体自振特性的影响,该文针对国内某一特高混凝土拱坝振动台试验模型,利用有限元方法计算分析了不同影响因素参数变化对坝体自振特性的影响。结果表明:(1)地基边界弹模变化对大坝前6阶自振频率影响很小;(2)坝体自振频率随单层坝体材料弹模呈正相关变化,且5~8层坝体弹模变化对坝体自振频率影响相对较大;(3)当地基材料弹模降低时,大坝自振频率降幅明显。当地基弹模逐渐增大时,前两阶自振频率保持相对稳定,中高阶自振频率增幅较大;(4)胶体单独作用和胶与尼龙丝联合作用对坝体自振特性的影响均较小。

In order to analyze the influence of model boundaries and model materials of large-scale arch dam shaking table test on the natural vibration characteristics of the dam, based on the shaking table test model of a certain domestic ultra-high concrete arch dam,this paper uses the finite element method to calculate and analyze the influence of different influencing factors on the natural vibration characteristics of the dam. The results show:(1) The elastic mode change of the foundation boundary has little effect on the first 6-order natural frequency of the dam;(2) The natural frequency of the dam is positively correlated with the elastic modulus of the single-layer dam material,and the change of the elastic modulus of the 5~8 layer dam has a relatively large influence on the natural frequency of the dam;(3) When the elastic modulus of the foundation material decreases, the natural frequency of the dam decreases significantly.When the elastic modulus of the foundation increases gradually,the first two natural frequencies keep relatively stable, and the middle and high order natural frequencies increase greatly;(4) Both adhesive and nylon wire have insignificant impact on the natural vibration characteristics of dam.