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| Shaking table tests on dynamic amplification and failure mechanism of layered rock slopes under seismic actions |
| WU Duohua1，2，LIU Yaqun1，LI Haibo1，XIA Xiang1，PENG Bo1，2，SHEN Hui1，2#br# |
| (1. State Key Laboratory of Geomechanics and Geotechnical Engineering，Institute of Rock and Soil Mechanics，Chinese Academy of Sciences，Wuhan，Hubei 430071，China；2. University of Chinese Academy of Sciences，Beijing 100049，China) |
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Abstract Large-scale shaking table tests on a layered rock slope with a size similarity of 1∶100 were conducted based on the Ganmofang landslide in Anxian，Sichuan province, and the dynamic response and failure mechanism of the layered rock slope under earthquakes were studied by successively loading seismic waves with different amplitudes，frequencies and durations. The results show that the frequency and amplitude of seismic waves have great influences on the acceleration dynamic response of the slope. The horizontal PGA amplification factors increase with increasing the frequency of input seismic waves when the input frequency is less than the initial natural frequency of the slope. However，the horizontal PGA amplification factors decrease with increasing the input frequency when the input frequency is greater than the initial natural frequency of the slope. The horizontal PGA amplification factors also increase with increasing the amplitude of input seismic waves when the input frequency is less than the initial natural frequency of the slope. However，the influence of lower amplitude seismic waves on the horizontal PGA amplification factors is more significant when the input frequency is close to or greater than the initial natural frequency of the slope. It is also shown that the duration of seismic loads has no obvious influence on the dynamic response of the slope. Analysis of both the induced displacement of the slope and the video recording of the test shows that the displacement dynamic response at the slope crest is more significant compared with other parts of the slope. When the amplitude of input seismic waves is 0.6 g，the slope is in a critical state with a critical displacement of about 7.3 cm，the determination of which is the basis and prerequisite for the evaluation of slope stability under seismic loads by using critical displacement in subsequent studies. The failure mechanism of the layered rock slope under seismic loads is loosening and cracking of the slope crest，uplifting of the lower part of the slope，developing and connecting of the potential sliding plane from the slope crest to the lower part of the slope，and finally shallow landsliding. The present study reveals the dynamic amplification effect and failure mechanism of layered rock slopes under seismic loads，and provides a useful reference for the seismic resistance design of engineering slopes and the prevention and reduction of disasters.
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2020, Vol. 39 
