Effects of near-fault ground motions on dynamic response of slopes based on shaking table model tests

Slope instability and failure frequently occur in areas near faults. A series of shaking table model tests were conducted to examine dynamic response of slopes to near-fault ground motion in the time and frequency domains. Effects of the intensity and pulse characteristics of near-fault ground motions on slope response were examined. Test results show that peak ground acceleration (PGA) induced by near-fault ground motion is amplified by elevation. When the amplitude of seismic loading exceeds a critical value (which is between 0.2 g and 0.5 g), intensity of near-fault ground motion increases, amplification of PGA by elevation weakens, and the high-frequency filtering effect of the slope is enhanced. Amplification of PGA by elevation and interfacial reflections are more prominent under pulse-like than non-pulse-like waves. The PGA amplification factor of the slope crest under pulse-like wave is 1.2 times of that triggered by non-pulse-like wave. Due to the interfacial reflections, vertical accelerations can be monitored simultaneously in cases which have only horizontal seismic loadings. The vertical PGA is 72.4% of horizontal PGA when the intensity of pulse-like waves is 1.1 g. These findings can provide a basis for designing earthquake-resistant of slopes near faults.