Abstract: The earthquake input model is fundamental in seismic responses analysis of a gravity dam. This paper first presents a theoretical analysis on the characteristics of motion fields that are expressed by four earthquake input models, then uses a random wavefield method to quantify incident waves and the corresponding ground motions, which ensures the unified input criterion shared by different earthquake input models. Finally, we simulate the seismic responses of a gravity dam using different earthquake input models, and offer a quantitative demonstration of the radiation-damping effect and complicated wavefield effect. The dam responses calculated using different earthquake input models are similar in trends, but their magnitudes are considerably different. For peak σ1 at the dam heel, the responses vary in the range of -68.2% to -14.8% caused by the radiation-damping effect, and -8.7% to 53.0% by the complex wavefield effect. This study reveals the influence of the complex wavefield effect, promoting the development of seismic response analysis of gravity dams.

Key words: gravity dam, earthquake input model, non-uniform wave input model, complex wavefield effect, radiation-damping effect