Shaking Table Test on the Seismic Behavior of Fractured Rock Slopes with Dipping and Anti-dipping Layered Structures

ABSTRACT Rock slopes with layered fractured structure are widely distributed in the mountainous areas of Southwest China. Under earthquake, these slopes are highly susceptible to disasters such as collapse, landslides, etc., adversely impacting the operation safety of transportation systems. This study aims to investigate the difference in seismic behaviors of two types of fractured rock slopes with typical dipping and anti-dipping layered structures. To do so, two sets of large-scale shaking table tests on the two typical fractured rock slopes were performed. The emphasis was made on the different failure mechanism of these slopes tested when subjected to four different seismic loadings with step-wise increase in amplitudes up to 0.7 g. We observed a three-stage destabilization process in both cases. For the dipping slope, the initial formation of microcracks and then their rapid development was followed by generation of terraced sliding surface through slope, whereas the formation of microcracks was followed by toppling of rock front until final collapse for the anti-dipping slope. Both slopes exhibit elevation amplification effects upon seismic loads as previously observed in other studies of similar slopes. The acceleration amplification effects near the bedrock interface and within slopes are more significant in the dipping case compared to the anti-dipping one. These effects are much enhanced at the top of slopes considered when the peak input acceleration exceeds 0.4 g. Further, Hilbert marginal spectrum analysis indicates that a sliding failure surface above the midslope was formed for the dipping slope, whereas the anti-dipping slope experienced more severe damages at the slope shoulder. The outcomes of this study are of important potential to assist the risk assessment and early warning of seismic hazards of fractured rock slopes.