地震波倾斜入射对土石坝动力反应的影响

Influence of Oblique Incidence of Seismic Waves on Dynamic Response to Rock-fill Dam

为研究土石坝在地震波倾斜入射时的动力反应,采用粘性人工边界及其对应的等效荷载地震动输入方法,对某典型土石坝有限元模型,分别计算了SV波和P波以不同角度、不同方向入射时的坝体动力反应,探讨了坝顶加速度放大系数随入射角度的变化规律。结果表明,随地震波入射角度的变化,坝顶加速度反应存在明显的差异,且在入射角度较大时表现得更加显著,说明行波效应的影响增强;此外,地震波自上、下游两侧入射时的结果截然不同。因此,在土石坝抗震设计及安全评价中,考虑地震波倾斜入射以及行波效应的影响是十分必要的。

In order to study on the dynamic response of rock-fill dam under oblique incidence seismic waves, it was realized by input equivalent load applied to the viscous artificial boundary. And then the method was applied to the dynamic response analysis of a typical rock-fill dam finite element model under SV and P waves by different incident angles and direction. Finally, the crest acceleration amplification coefficient variation of the incidence angles was discussed. The results show that the crest acceleration response was obvious different with seismic waves in different incidence angles and the performance was more significant in large incidence angles, illustrating the effect of travelling waves gradually increased. In addition, the results were quite different when incidence of seismic waves from upriver and downriver. Therefore, the effect of oblique incidence of seismic waves and travelling waves should be considered in seismic response analysis of rock-fill dam and safety evaluation.