Shaking Table Test on Dynamic Damage Characteristics of Bedrock and Overburden Layer Slopes

摘要

This article performs groups of shaking table tests to study the dynamic damage characteristics of the slope that is composed with inclined bedrock, upper overburden soil layer, and weak soil interlayer. The prototype is of the entrance slope of the Mount Zheduo tunnel, which is located in the mountains of the western Sichuan Plateau in China. The test model is designed based on the similarity theory. The peak ground acceleration (PGA) amplification coefficient, Fourier transform, and transfer function theory are employed to analyze the test results. The results before slope failure indicate that the PGA amplification coefficient of both the overburden layer and the weak interlayer increases as the excitation intensity increases. At the same time, the dynamic response of weak interlayer is amplified on low-frequency wave excitation while that is impaired when high-frequency seismic waves dominate. When the slope is damaged, the slope undergoes large shear deformation: the whole overburden layer slides along the weak interlayer, and the PGA amplification coefficient of the weak interlayer sharply decreases. The frequency response function indicates that the vibration relationship between the upper part of the weak interlayer and the slope surface is very close, and the slope surface vibration may be mainly affected by the vibration in the upper part of the weak interlayer, which reflects the early predictability in the failure symptoms of the slope.