【摘要】 进行拱坝抗震安全性评价时，需考虑地震动的不确定性。基于物理机制的地震动直接数值模拟方法，可以考虑不同地震情景，生成与断层破裂机制和场地条件相关的地震动，在地震工程领域具有广阔的应用前景。本文旨在研究直接数值模拟地震动作用下，拱坝非线性动力响应的不确定性。采用直接数值模拟方法得到3组情景地震动作为动力荷载，研究了GX拱坝的非线性动力响应，对比分析了坝体混凝土损伤、横缝开度与位移。结果表明：即使在发震断层、震级与坝址处顺河向地震动峰值加速度均保持一致的情况下，不同情景地震动作用时，坝体的地震响应水平也存在显著的离散性。本文采用基于直接数值模拟得到的地震动进行拱坝动力分析，研究了坝体响应的离散性，可为直接数值模拟地震动的应用提供参考。更多还原

【Abstract】 Uncertainty in ground motions is a significant factor in the seismic safety evaluation of arch dams. The physical-based direct numerical modeling can consider different earthquake scenarios and generate site-specific earthquake motions, manifesting great application prospects in earthquake engineering. This study examines the scattering of nonlinear seismic responses of an arch dam to ground motions that are simulated numerically for three earthquake scenarios, focusing on the dynamic responses-including concrete damage, contraction joint opening, and displacement. Results show that the responses feature significant variability under different earthquake scenarios even if the rupture fault,magnitude, and stream peak ground acceleration at the dam site all remain consistent. The findings shed light on the scattering of dam responses and promote application of the ground motions generated by direct numerical simulations.更多还原