Investigation of Landslide Behavior under Unidirectional and Bidirectional Seismic Ground Motions Based on Shaking Table Model Tests

Many post-earthquake geological disaster investigations have proved that vertical seismic ground motion has great impact on slope failure and landslide movement behavior. To explore the impact of vertical seismic force on landslide behavior, a set of slope shaking table model tests were designed and performed. A special slope shaking table model was first built to properly consider the entire deformation evolution characteristics of landslides under earthquakes, and different unidirectional and bidirectional seismic ground motions were input into the shaking table model for the experiments. Contact and noncontact measurement systems were both arranged to record seismic responses and landslide evolution characteristics under unidirectional and bidirectional ground motions. Horizontal and vertical acceleration amplification characteristics inside the slope, slope crest settlement, landslide configuration evolution characteristic, and landslide movement behavior were comprehensively presented and analyzed. The acceleration responses inside the slope show different changing characteristics under unidirectional and bidirectional seismic forces. The arranged noncontact measurement systems, including laser displacement meters and particle image velocimetry technology, indicate that slope crest settlement, landslide movement velocity, and landslide runout under bidirectional seismic ground motions are all greater than that of the slope under unidirectional earthquake action. All these results demonstrate that vertical earthquake loading has a nonnegligible effect on slope seismic responses and landslide movement behavior. This effect is better to properly consider, and thus further promote the development of slope seismic design methods, as well as the prevention and control of slope seismic geological hazards.