用有限元和无穷元耦合模型计算了半圆形河谷在单位脉冲入射下的河谷地面反应，从而分析了地震波的入射方向对河谷岸坡放大系数的影响．岸坡放大系数定义为：河谷沿岸不同高程处的地震动峰值加速度与河谷底处地震动峰值加速度之比．因此，岸坡放大系数的变化将改变拱坝的应力和应力分布．研究表明：地震波人射角的轻微变化将对河谷岸坡放大系数产生极大影响，这说明高拱坝的抗震分析宜考虑输入地震波的不同入射方向的作用． The coupling of the finite element and the infinite element model was used to calculate the ground response of the valley in the semicircular valley under the incident pulse of the unit. The effect of the incident direction of the seismic wave on the amplification factor of the valley bank was analyzed. The slope amplification factor is defined as the ratio of the peak acceleration of ground motions at different elevations along the river valley to the peak acceleration of earthquakes at the bottom of the river valley. Therefore, the change of amplification factor of bank slope will change the stress and stress distribution of arch dam. The results show that the slight variation of the angle of the seismic wave will have a great influence on the amplification factor of the valley bank, which shows that the seismic response analysis of the high arch dam should consider the different incident directions of the input seismic wave.