Seismic response of an embankment slope reinforced with rubble mound: centrifuge model testing and analytical validation

Abstract

The topography of an embankment slope can lead to acceleration amplification during an earthquake, potentially damaging structures installed on the embankment. This study performs dynamic centrifuge model tests and numerical modeling on embankment slopes with a pile-supported wharf structure to investigate the acceleration response and variation in seismic stability depending on the form of rubble mound reinforcement. The results show that installing a rubble mound reduces the peak horizontal acceleration response of the embankment slope by up to 45%, and decreases the spectral acceleration within the range of the natural period of the structure by up to 18%. The factor of safety (FS) for the embankment slope also increases by up to 25% owing to the rubble mound reinforcement. However, a constant 2–m thickness of the rubble mound is essential to ensure slope stability. The effects of any additional thickness are limited (e.g., the FS ranges from 1.34 to 1.41, with the rate of change in the FS with respect to the seismic horizontal coefficient being 3.5–3.7). Thus, installing only a constant 2–m thick rubble mound can adequately secure both the seismic response reduction in the wharf structure and seismic stability of the embankment slope.