高拱坝动力试验模型气幕隔震的数值模拟及试验研究

Numerical simulation and experimental research of dynamic experimental model of high arch dam with air-cushion isolation

基于坝体坝基相互作用和流体-气体-固体耦合理论模型,采用动力有限元时程分析的数值仿真方法,对锦屏一级高拱坝动力试验的模型,进行了气幕隔震的三维数值模拟。基于动力试验模型的相似原理、模型材料的单轴抗压强度试验以及超声波检测,得到了试验模型的基本相似物理参数;保证试验模型的基本动力相似;气室材料采用厚度为1 cm的工程塑料ABS,坝体上游面的左、右两岸直接用聚苯乙烯塑料(简称ABS)拉通覆盖,均匀地分布在坝体上游面,达到整体气室隔震的效果。数值计算及试验结果基本相符,气幕显著降低了上游坝面的动水压力。与无气幕相比,动水压力削减可达70%以上。通过数值计算分析及试验研究相结合的手段,论证了气幕减震蕴含的工程价值。

Based on the theoretical model of dam-foundation interaction and the fluid-gas-solid coupling,the 3D FEM numerical simulation has been carried out for the experimental model of Jinping high arch dam with consideration of air-cushion isolation.According to the similarity principle of dynamic experiment and the uniaxial compressive strength tests as well as the ultrasonic detection,the basic physical parameters of the experimental model are obtained,which could guarantee the basic dynamic similarity of experimental model.To achieve the goal of the isolated effect of the whole air-cushion,the engineering plastics acrylonitrile butadiene styrene（ABS for short） is adopted for the air-cushion,which is used for covering on the upstream of the dam model evenly.The experimental and numerical results show that the hydrodynamic pressure is reduced by air-cushion significantly.Compared to the case without air-cushion,the hydrodynamic pressure can be reduced for more than 70%.The feasibility and the implying engineering value of the air-cushion isolation have been demonstrated through the results of numerical simulation and experimental research.