Experimental study of the dynamic response and failure mode of anti-dip rock slopes

The mechanisms and characteristics of earthquake-triggered anti-dip rock landslides remain largely unknown. In this study, the dynamic response characteristics and failure process of anti-dip layered rock slopes are investigated under strong earthquake conditions using shaking table model tests and numerical analysis. The test model uses a slope angle of 60° and steep dip angle of 75° and considers different vibration waveforms, frequencies, amplitudes, and durations. Under the same conditions, the seismic wave PGA amplification factor is higher than that of a sine wave. Under the action of the two waveforms, the PGA amplification factor increases nonlinearly with elevation owing to the interaction of the elevation amplification effect and inhibition of the slope toe. The frequency is greater than or equal to the natural frequency of the test model, but the increase is not notable below 3/5 of the slope height. Horizontally, the PGA amplification factor is larger on the top and surface of the slope. The peak PGA amplification factor shifts from the surface to the top with increasing amplitude. With increasing frequency, the PGA amplification factor reaches a peak value at the natural frequency and then decreases. Frequency has a stronger influence on the dynamic slope response than amplitude, and duration has the weakest influence. The dynamic slope failure model results show that the failure mode of an anti-dip rock slope under a seismic load involves the extension of shear cracks and tension cracks and development of step-type fractures, which trigger slope toppling and sliding failure.