水平成层场地动力特性研究

为了探究地震波作用下水平成层场地的动力响应特征，设计并开展了水平成层场地的大型振动台模型试验，并基于希尔伯特-黄变换对水平成层场地在时域和频域的响应进行了研究.研究结果表明:地震波在水平成层场地内自下而上传播过程中被放大，场地表层碎石土层对地震波的放大效应强于下覆软岩层和硬岩层，碎石土层加速度放大系数达到5.94；地震波从硬岩层传入软岩层时，高频成分（27~40 Hz）被吸收，低频成分（0~22 Hz）被放大，地震波从软岩层传入碎石土层时，7~27 Hz频段进一步被放大，同时，碎石土层内的地震波表现出双卓越周期特性；反应谱峰值随着输入地震波幅值的增大而增大；软岩地层在反应谱周期T0.3 s部分表现出衰减效应，在周期T0.3 s 部分，自下而上3个地层的反应谱表现出放大效应；碎石土层/软岩层分界面对地震波能量具有一定的聚集和放大作用；软岩层/硬岩层分界面对地震波的能量仅仅表现为聚集作用；在碎石土层内，地震波的能量被放大，Hilbert能量谱由单峰发展为三峰，峰值在时间轴上向坐标轴正方向发散，在频率轴上由低频向高频移动. 

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 T0.3 s of response spectrum, while at the period T0.3 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.