Dynamic Response and Failure Process of a Counter-Bedding Rock Slope under Strong Earthquake Conditions

There are massive landslides and potential landslides along the Three Rivers Basin in the Qinghai-Tibet Plateau, which pose a serious threat to the Sichuan-Tibet Railway. A normal shaking table model test was conducted to study the dynamic characteristics and dynamic response of a symmetrical counter-bedding rock slope based on the Zongrong Village landslide. The influences of the dynamic parameters, seismic wave type, and a weak intercalated layer on the slope's dynamic response were considered. The results showed symmetry between the growth trend of the acceleration amplification factor and other research results. When the input wave amplitude was constant, the acceleration amplification factor increased at first and then decreased as the frequency increased. When the input frequency was near the slope's natural frequency, the acceleration amplification factor increased at first and then decreased with an increase in the input amplitude and reached the maximum value at 0.3 g. The acceleration amplification factor increased linearly with height in the vertical direction inside the slope but increased slowly at first and then sharply along the slope surface, reaching the maximum value at the slope's top and exhibiting an obvious "elevation effect". When sinusoidal waves, Wolong waves, and Maoxian waves with the same amplitude were input, the slope's amplification effect on the bedrock wave was more obvious. The weak intercalated layer showed the phenomenon of "thin layer amplification" and "thick layer attenuation" in response to the input seismic wave. The slope's failure process can be roughly divided into three stages: (1) the formation of tensile cracks at the top and shear cracks at the toe; (2) the extension of cracks and the sliding of the slope-surface block; (3) the formation of the main sliding surface.