Shaking table test for seismic responses of slopes with a weak interlayer

The weak layer in a slope always controls slope deformation and failure mode. Under an earthquake, the complex interaction mechanism between the weak interlayer and the seismic waves hinders the understanding of the dynamic responses of this type of slope. Based on the existing knowledge, shaking table tests were conducted for four slope models containing a weak interlayer. The effects of the weak interlayer were uncovered by comparing the responses of the models with and without a weak interlayer. Both the horizontal(PHA) and vertical(PHA) acceleration responses were amplified along the altitude for all four slope models, especially in the locations with the elevation higher than the interlayer. In the locations with the elevation lower than the interlayer, the PHA amplification factor remained within 1.5. In comparison with the homogeneous model, the existence of an interlayer resulted the two component responses in the upper part of slope strongly depended on the features of the interlayer and the input intensity. When the input intensity was weak(≤0.3g), the responses for the models with a thin or a thick interlayer were stronger than in the homogenous model. With the increasing of the input intensity, the thick interlayer generated an effect of seismic isolation, which caused the PHA and PVA responses at the slope crest decreasing by 50% and 70% respectively. The horizontal displacements on the slope surface were amplified and reached the maximum value at the crest. The initial deformation occurred at the top of for the homogeneous model slope. However, for the four models with a weak interlayer, the deformation was firstly observed in the position above the interlayer and below the crest. The location and the degree of the slope failure were closely related to the thickness and the dipping angle of the weak interlayer. The model with a horizontal interlayer caused the failure location higher than the models with an anti-dip interlayer and the model with a thin interlayer caused the failure more severe than the one with a thick interlayer. ©, 2015, Academia Sinica. All right reserved.