【摘要】 结合南水北调中线工程穿南沙河倒虹吸结构,建立了考虑流固耦合的箱型倒虹吸动力分析有限元模型,基于子空间法,对不同过水工况和地质条件下结构的动力特性进行了分析。结果表明:倒虹吸过水情况和地基土均匀性对结构自振频率和振型有显著影响;结构埋置深度对其自振特性有较为显著的影响,埋深越浅,前阶主频率越大,振型改变越明显;土层分布越均匀,土壤黏聚力越大,结构的自振频率越小,振动形态越稳定;可通过调整管体过水量和换填土层改善结构动力特性。更多还原

【Abstract】 Combined with Nansha River inverted siphon of Middle Route of South to North Water Transfer Project,a FEM dynamic analysis model for the inverted siphon was made considering fluid-structure coupling.Based on subspace method,the dynamic characteristics in different load cases and geological conditions were analyzed.It is shown that the frequencies and the modes of the inverted siphon are obviously influenced by the water situation and the foundation soil uniformity.The buried depth has great effect on the structural natural vibration,i.e.the more shallow the buried depth is,the greater the front frequencies are.The relative modes change more obviously.If the soil layers are better distributed and the soil cohesions are greater,the natural vibrating frequencies are less and the vibrating shapes are more stable.Therefore,the dynamic characteristics can be bettered by water-adjusting and soil-replacing.更多还原