Responses of a Cantilever Retaining Wall Subjected to Asymmetric Near-Fault Ground Motions

Fault rupture produces pulse-like ground motions in the near-fault regions, which are significantly different from ordinary ground motions in the far-field regions with respect to both intensity and frequency contents. The pulse-like ground motions are characterized as high amplitude and long period pulses that could cause severe damage to structures. In this study, we investigated how the pulse-like ground motions have effects on the responses of a cantilever retaining wall by performing a series of numerical simulations. The seismic behaviors of the retaining wall were numerically modeled by adopting a finite difference scheme. High amplitude ground motions scaled to a fixed PGA were first collected as an input dataset and classified into pulse-like, non-pulse-like, and ambiguous motions by a pulse indicator. Then, differences in the development of displacements at the wall were quantitatively compared between the types of the motions. Additional simulations were carried out with the original and inverted input ground motions to investigate the effect of asymmetry of ground motion on the wall responses. It turned out that the asymmetrical ground motions with larger velocity amplitudes in the direction coincide with the relative wall movement could generate significant wall displacements.