拱坝溢流水舌冲击下游河床诱发坝体振动的研究

Research of arch dam vibration induced by the spillway flood flow nape dropping on the river bed

本文以二滩双曲拱坝为背景,运用随机振动理论,讨论了拱坝溢流水舌冲击下游河床诱发坝体振动问题。在研究时将水力模型观测出的溢流水舌冲击下游河床的脉动荷载,加到“坝体-库水-基础”等联合体的力学模型上,求出坝体的振动。结果说明,二滩双曲拱坝表孔溢流水舌冲击下游河床的脉动荷载,对坝体的振动影响很小,对坝体的安全不构成威胁。本文所述的基本概念也适用于其它随机荷载作用下结构的振动问题分析。

In this paper, taking Er-tan dual curved arch dam as an example the authors investigate the vibration of dam body induced by the spillway flood flow nape dropping on the river bed by means of the theory of random vibration. Firstly from a series of hydraulic model tests those fluctuating pressures under the above mentioned flow condition were recorded. Then in the mechanical model of 'dam-reservoir water-foundation' these recorded pressures were input. Thereby the vibration reaction of dam body could be measured. Test result shows that the effect of dynamic action of dropping water on dam body of Er-tan dual curved arch dam is negligible. Meanwhile this basic conception can be also be applied to other structural dynamic analysis under the action of random loading.