地震荷载作用下确定土的阻尼比的频域分析法

Frequency domain analysis in determining damping ratio of soil under seismic load

为了从频域角度分析地震荷载作用下土的阻尼比,将随机过程理论引入土阻尼比分析中,并提出了一种基于傅里叶变换的频域分析法,最后通过试验及数值分析手段验证了利用该方法确定土的阻尼比的可行性。结果表明:通过傅里叶变换的频域分析方法得到的地震荷载下土的阻尼比是一个与频率相关的函数;任意一种土及地震波都可得到一条"阻尼比-频率谱"。实际工程应用时,建议将土阻尼比看作随地震波输入过程而动态变化的参数。通过此频域分析法可找到每类土、每种地震波作用下的"阻尼比-频率谱",即可得到土的动态阻尼比参数。以期为随机荷载作用下土阻尼比的确定提供参考。

In order to analyze the damping ratio of soil under seismic load in frequency domain,stochastic process theory was introduced into soil damping ratio analysis.A frequency domain analysis method based on Fourier transform was proposed,and the feasibility of this method was verified by experiment and numerical analysis.The results showed that the damping ratio of soil under seismic load was a frequency-dependent function obtained by the frequency domain analysis method of Fourier transform.Any kind of soil and seismic wave can get a "damping ratio-frequency spectrum".We suggest that the soildamping ratio should be regarded as a parameter that changes dynamically with the seismic wave input process.Through this frequency-domain analysis method,the "damping ratio-frequency spectrum"of every soil and every seismic wave can be found,and the dynamic damping ratio parameters can be obtained.In order to provide a reference for the determination of soil damping ratio under random load.