中文摘要：

为了分析地下厂房围岩边界条件对机墩动力特性的影响以及不同数值模型取值范围对机墩振幅计算结果的影响，结合某水电站地下厂房实际情况，建立了三维有限元数值模型。计算结果表明：厂房边界弹性支撑的增强有助于机墩、风罩的抗振，风罩壁厚的增加对增强机墩、风罩抗振能力效果不明显；采用动力谐响应分析方法计算机墩振幅时，数值模型的取值范围对振幅计算结果有较大影响；计算机墩振幅时，建议采用厂房整体模型，但现行规范中推荐的机组振动荷载需进一步论证确定。

英文摘要：

A 3D numerical model was set to analyze the influence of different rock boundary conditions on the dynamic characteristics of generator pier and the influence of different ranges of numerical model on the amplitude of generator pier. The results show that the enhancement of elastic support of hydropower house＆#39;s boundary is beneficial to the anti-vibration of generator pier and ventilation barrel. The increase in thickness of ventilation barrel has less contribution to enhance the anti-vibration ability of generator pier. When harmonic response method is used to check the amplitude of generator pier, the range of numerical model has great influence on the result. The integral model of the powerhouse is suggested to be adopted for calculating the amplitude of generator pier. However, the vibration loads, recommended by the present specification, need further clarifications.