Seismic response of horizontal layered site

A large scale shaking table test of horizontal layered site was conducted, and based on which the seismic response of horizontal layered site was researched in this paper. The research results show that: the seismic wave is amplified when propagating from bottom to top of test model, the amplification effect in gravel soil layer is stronger than that in soft rock layer and hard rock layer, and the acceleration amplification factor in the gravel soil layer reaches 5.94. In the propagation process of seismic wave from hard rock layer to soft rock layer, the high-frequency components with 27-40 Hz are absorbed and the frequency components with 0-22 Hz are amplified, in the propagation process of seismic wave from soft rock layer to gravel soil layer, the frequency components with 7-27 Hz are amplified further. Meanwhile, the seismic wave in the gravel soil layer presents two predominant periods. The peak values of the response spectra increase with the input seismic wave amplitude. At the same time, the seismic wave in gravel soil layer has two predominant periods. The peak values of response spectra increase with increasing the input seismic wave amplitude. The soft rock layer presents attenuation effect at the period T≤0.3 s of response spectrum, while at the period T>0.3 s, the response spectrum presents amplification effect from hard rock layer to gravel soil layer. The interface between gravel soil layer and hard rock layer will gather and amplify the energy of earthquake wave, while the interface between soft rock layer and hard rock layer will just gather the energy of seismic wave. In the gravel soil layer, the energy of earthquake wave is amplified and the Hilbert energy spectrum develops to have three peaks, the peaks of Hilbert energy spectra divulge to the forward direction of time axis, and move to high frequency part from low frequency part in frequency axis. © 2016, Editorial Department of Journal of Southwest Jiaotong University. All right reserved.