Impacts of ground motion characteristics on liquefaction triggering and lateral displacement of a sloping ground

抄録

Subduction motions typically exhibit lower amplitudes, longer durations, and lower frequencies compared to crustal motions. This paper initiates the assessment of how these ground motion characteristics impact liquefaction-induced responses in sloping ground by presenting a numerical study that isolates these effects. In an initial endeavor to dissect and understand the effects of these variables, single-frequency sinusoidal ramp waves with varying amplitudes, durations, and frequencies are used in this study for fully coupled nonlinear dynamic analysis of a mildly-sloping liquefiable soil column. The analyses are carried out in OpenSees using the SANISAND-MSf v2 soil constitutive model. The simulation results indicate that increasing the maximum amplitude of the base excitation leads to a decrease in the number of cycles required to trigger liquefaction, while simultaneously increasing the end-of-motion surface lateral displacement. Increasing the number of cycles with the maximum amplitude would not affect the pre-liquefaction response if the triggering happens in the early loading cycles, but can increase the surface lateral displacements as the soil remains in the post-liquefaction stage for a longer duration. Both pre- and post-liquefaction soil responses under various motion frequencies can exhibit distinct patterns depending on the intensity of the motion and the natural frequency of the soil column.