Cumulative damage evolution and failure modes of the bedding rock slope under frequent microseisms

Most previous studies focused on the performance of bedding rock slope under strong earthquakes, where limited publications involved bedding rock slope under microseisms. Present literatures often ignored the effect of rock joint surface shapes on slope stability and just simplified it as a planar surface, which is always not practical. In this study, shaking table test was carried out to study the dynamic behavior, damage accumulation, and failure mode of the bedding rock slope with zigzag asperities under frequent microseisms. Generally, the natural frequency decreases with the increase of loading times of earthquakes, while the damping ratio of the slope has a tendency to grow with it. Results shows that the main failure mode of model slope was integral slipping along the bedding surface, and two sliding surfaces were observed during the instability evolution process of the model slope, indicating that the deformation pattern of the sliding surface was mostly determined by undulating angles and normal stress. Besides, the cumulative damage of the slope was evaluated based on the variation of natural frequency, and the cumulative damage evolution models of slope rock mass were established respectively for stages of micro-small earthquakes and strong earthquakes. It is found that the evolution curve of cumulative damage was characterized by a tendency of slight decline to rapid growth to steady growth under micro-small earthquakes, while it followed an exponential growth trend under strong earthquakes.