The Effect of Earthquake Motion on Rockfall with Material Property Variation

Abstract

In this study, the Discrete Element Method (DEM) is employed to simulate earthquake-induced rockfalls by assigning displacement information to the slope. Under earthquake conditions, rockfall experiences two modes in the earthquakes, referred to as the rolling & sliding mode and the jumping mode. The categorization of these two modes is judged by the occurrence of jumping. Additionally, this study investigates the effects of the two parameters of the earthquake wave, frequency and amplitude, on rockfall movements by using three rock shapes in different roundness with assuming a sinusoidal earthquake wave. The findings reveal that the high frequency tends to facilitate a transition of rockfalls from the rolling & sliding mode to the jumping mode. With a comparison between the two modes in earthquake motion, it is found that the jumping mode has a significant effect on rockfall movements because for the rolling & sliding mode, the ratio of rockfall movements under earthquake and non-earthquake is in a range of 0.78~1.44 while for the jumping mode, it is in a range of 0.76~5.88. Finally, the 2016 Kumamoto earthquake is employed to have an evaluation of rockfalls with consideration of earthquake motion and material property variation.