混凝土重力坝气幕隔震效果研究

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振动与冲击 ›› 2014, Vol. 33 ›› Issue (23) : 190-194.

论文

混凝土重力坝气幕隔震效果研究

陈江1,2，熊峰1,2

作者信息 +

Study of Air-cushion Isolation Effects in Concrete Gravity Dam

Chen Jiang1,2, Xiong Feng1,2

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文章历史 +

摘要

基于气幕隔震控制的气-液-固三相耦合数值模型，在该模型中考虑了坝体混凝土的开裂行为，采用黏弹性人工边界模拟坝基截断边界的辐射阻尼效应，首次完成了混凝土重力坝气幕隔震效果的三维非线性数值模拟。结果表明：气幕可以有效降低坝体上游面的动水压力及坝体加速度反应，从而减小坝体的开裂范围。随着气幕厚度的增大，动水压力和加速度削减越多，削减幅度的提高率递减。采用变厚度气幕能提高利用率，更有效地发挥气幕的隔震效果，本文工况，变厚度气幕对混凝土重力坝动水压力极值的削减幅度约为50%，坝顶加速度峰值的消减幅度超过30%。

Abstract

The gas-liquid-solid tri-phase coupling numerical model of the air-cushion isolation control was presented in this paper, in which the cracking behavior of concrete was considered. The radiation damping effect on truncated boundary of dam foundation was considered by using viscous-spring artificial boundary condition. The 3D nonlinearity simulation of air-cushion isolation effects in concrete gravity dam was carried out for the first time. It shows that air-cushion reduces the hydrodynamic pressure and acceleration effectively, so the cracking range of dam body are decreased. As the thickness of air-cushion increases, the reduction of hydrodynamic pressure and acceleration increases, the increment rate of reduction degree decreases progressively. Compared with uniform-thickness air-cushion, variable-thickness air-cushion can improve the utilization ratio and develop the air-cushion isolation effects more effectively. In the various cases of this paper, the maximum of hydrodynamic pressure is reduced by 50% approximately, the maximum of dam crest acceleration is reduced by more than 30% with variable-thickness air-cushion.