Centrifuge modeling and analytical validation of seismic amplification in a slope during earthquakes – Implications to seismic slope stability analysis

Abstract

Earthquake-induced slope failure causes enormous damage to structures above and below the slope. The acceleration amplified within the slope directly degrades the stability of the slope. However, the seismic amplification characteristics within a slope during earthquakes remains poorly identified. This study explores seismic amplification of a slope during earthquakes through dynamic centrifuge tests. Comparison of the acceleration amplification patterns between a slope model and a flat ground model revealed that the acceleration was concentrated at the crest and near the slope surface. This phenomenon was verified through the analytical model developed based on a multi-degree of freedom mass-damper-spring system. In addition, the analytical model enabled the computation of the peak acceleration at each part of the slope and allowed examination of the factor of safety for slope stability. While various locations within a slope can be chosen to determine the representative acceleration as well as the free-field flat ground response, the use of the acceleration at the crest resulted in the lowest factor of safety value. Therefore, a conservative analysis would preferably use the accelerations at the crest and on the slope surface, rather than using the accelerations in a free-field flat ground. This study presents unique ground acceleration data from the well-controlled physical modeling of a slope and a simple but robust analytical model to predict seismic amplification in a slope, which provides better insight into determination of ground acceleration for slope stability analysis.