库底吸收对重力坝动力响应的影响分析

水库库底吸收是重力坝-地基-库水系统在地震作用下相互作用中的重要组成部分。本文基于声固耦合方法结合阻抗边界条件可以对水库库底吸收进行模拟，通过算例验证可知无论是激励频率相同库底反射系数不同还是激励频率不同库底反射系数相同两种情况都可以得到准确的坝面动水压力分布曲线。通过对丰满新建重力坝的分析可以得到的结论为不同库底反射系数对坝面动水压力分布有显著影响，动水压力幅值随着库底反射系数的增加而变大，坝体动力响应也随之变大；讨论了丰满老坝对新坝坝面动水压力分布的影响，由于上游老坝的存在，新坝整个坝面上动水压力幅值明显变大。

Effects of reservoir bottom wave absorption on dynamic response of gravity dams

Reservoir bottom wave absorption is an important part of the interaction in a gravity damfoundation-reservoir system.In this study,the absorption is simulated using an acoustic structure coupling method and impedance boundary conditions.An example verification analysis shows that an accurate curve of hydrodynamic pressure distribution over the dam surface can be obtained in the case of different coefficients of reservoir bottom reflection at the same excitation frequency or the case of these coefficients taking the same value at different excitation frequencies.Analysis of the new Fengman gravity dam supports the conclusion that the reflection coefficient has significant influence on the pressure distribution,and an increase in the coefficient will enhance the amplitude of hydrodynamic pressure and consequently the dynamic response of the dam.The influence of the old Fengman dam,located in the upstream,on the new one is examined,revealing the existence of the old dam brings about significantly larger amplitudes in the variations of hydrodynamic pressure over the whole surface of the new dam.