基于流固耦合理论的泥石流冲击桥墩的动力响应分析

Dynamic responses analysis of debris flow impacting pier based on fluid-structre interaction theory

以双柱式桥墩结构为研究对象,基于流固耦合分析理论,采用ANSYS+CFX建了泥石流与双柱式桥墩的耦合分析模型,分析了在不同泥石流速度冲击时桥墩的响应情况。分析结果表明:该方法可以很好地模拟泥石流从进口到墩位处再到出口过程中整个流场的发展和分布情况;在泥石流冲击作用下,墩柱底部承受较大的横向冲击力,导致桥墩根部出现较大的负弯矩、拉应力和压应力,其值均随速度的增加而增大;上游立柱冲击力大于下游立柱的冲击力,而且进口流速越大其遮流作用也越大;由于双柱式桥墩结构横向刚度大,泥石流冲击产生的墩顶横向位移却很小;泥石流中的块石对桥墩的冲击影响较大,不可忽视。研究结果对双柱式桥墩预防泥石流冲击具有一定的参考价值。

Taking double-column bridge piers as research object and based on the coupled fluid-structure interaction theorem, a numerical analysis model for debris flow and bridge pier has been built using ANSYS+CFX.The responses of bridge piers were studied under impact load of debris flow with different velocities. Results show: This method can well simulate debris flow field and distribution from inlet to outlet;Under impact load of debris flow, bridge piers bear large lateral force which leads to larger moment, tensile stress and compressive stress at the root of bridge column;And impact force, moment, tensile stress and compressive stress increase with increasing flow velocity;The impact force of the upstream column is greater than the impact force of the downstream column, and the larger the inlet velocity, the greater the shielding effect;Due to the strong lateral stiffness of double column bridge piers,the displacement on the top of piers by impact of debris flow is very small;Impact force by stone in the debris flow is too large to not be ignored. These results of this paper are value to prevent double-column bridge piers from impacting by debris flow.