Dynamic response characteristics of a rock slope with discontinuous joints under the combined action of earthquakes and rapid water drawdown

In order to study the dynamic response characteristics of a rock slope with discontinuities under the combined action of earthquakes and rapid water drawdown, a large-scale shaking table test was performed on a rock slope with discontinuous joints. Wenchuan earthquake (WE) seismic records were performed to investigate the horizontal and vertical acceleration response and displacement response. In particular, three-dimensional optical measurement techniques was used to obtain the slope surface displacements. A comparison was made on the seismic response according to the analysis of PGD (peak ground displacement) and M (PGA) (acceleration amplification coefficient) of the modeled slope. The results show that the experimental slope mainly underwent settlement and horizontal deformation when the WE records were applied in the z and x directions, respectively. The slope was first shaken by the P wave, which caused the differential settlement to occur at the surface slope; then, the slope was shaken more severely by the S wave, which led to a greater horizontal deformation. Moreover, analysis of the Delta PGD (increment of PGD) and Delta M (PGA) (increment of M (PGA)) under rapid drawdown suggests that the rapid water drawdown mainly impacts the deformation of the surface slope, particularly between the high and low water levels. The water infiltration through the cracks softened the material of the surface slope, and the rapid drawdown also enhanced the slope deformation. In addition, the damage evolution process of the slope can be identified, mainly including three stages: an elastic stage (< 0.168 g), a plastic stage (0.168-0.336 g), and a failure stage (> 0.336 g).