【摘要】 传递函数分析对获取振动系统的动力特性参数及估算动力响应具有重要意义。边坡地震模拟振动台模型试验可求算两种传函:反映边坡各点的场地地震动特征的绝对加速度传函(基于测点实测加速度时程)和反映坡体本身振动性质的相对加速度传函(基于测点与坡脚即台面间的实测加速度相对时程)。以弹性体振动方程分析和试验实测,探讨了边坡振动台模型试验中动力特性参数计算的传函选择和以传递函数对动力响应的估算,得出结论:(1)不同于机械模态分析(以绝对传函的模和虚部计算动力特性参数具有等价性),对于边坡模型试验,绝对传函实部和模混入了台面加速度影响,以绝对传函虚部或相对传函虚部才能正确计算动力特性参数;(2)传递函数和台面输入波形Fourier谱的逐频相乘得到动力响应估算谱,与测点实测响应Fourier谱吻合较良好,这种估算方法有助于对不同地震波作用下的边坡动力响应作出总体评价,并指导模型试验中地震波形的合理选取。更多还原

【Abstract】 Transfer function analysis is an important method for obtaining dynamic characteristics parameters and estimating predictive dynamic response of vibration system.Through earthquake simulation shaking table model test of side slopes,transfer function of absolute acceleration and of relative acceleration could be obtained,which reflected the ground motion and the slope body’s seismic vibration respectively.Based on vibration equation analysis of elastomer and its demonstration model test of a side slope,calculation of dynamic characteristics parameters and predictive estimation of seismic response with transfer function analysis were studied.Two pieces of conclusion have been reached: First,in calculation of dynamic characteristics parameters,using the imaginary part of absolute or relative acceleration transfer function could get more reasonable and accurate result than using amplitude and real part.Second,the predictive Fourier spectra of slope’s seismic response could be estimated by multiplication of transfer function and Fourier spectra of input seismic excitation in frequency domain,and the estimation results was in accordance with model test data.It means that transfer function analysis is not only conducive to investigating slope’s essential response feature under complicated and various seismic motions,but also help to designing the shaking table board’s loading waveform of tests.更多还原