Large Shaking Table Test on Seismic Response of Site with Tilted Interlayer

To investigate the dynamic response of a complex site with a tilted interlayer and provide a potential reinforcement for the site, a large-scale shaking table model test was done to study the acceleration, strain and displacement responses of the site. The effects of the interlayer on the stability of the site are discussed based on an analysis of the Fourier spectrum and response spectrum under the El Centro seismic wave. Furthermore, the critical acceleration and stability factor of the site are obtained through a pseudo-static analysis. Experimental results show that the interlayer obviously weakens the peak acceleration of the seismic wave and that the degree of impairing effects intensifies with the seismic peak acceleration increasing. There is a feature of ‘magnitude saturation’ for the acceleration amplification coefficient (AAC) of the position of bedrock. The peak strain of the interlayer is greater than those of the other layers. When the input earthquake amplitude is larger than 0.33g, there is another peak strain in the cover layer which is located at a platform corner and the strain curve presents a form is ‘W’. The interlayer can also weaken to some extent the amplitude of the Fourier spectrum at about 20 Hz. The predominant periods of theresponse spectra measured from different cross sections of the same soil layer are similar, but obviously different between different soil layers. The predominant period of the interlayer (0.31 s) is greater than those of the bedrock layer (0.19 s) and the cover layer (0.21 s). According to the pseudo-static analysis, when the peak acceleration of the seismic wave loaded is 0.33g, the site stability factor is 3.16, and the critical acceleration of the potential slip area is 1.42g.