Centrifuge Studies of Topographic Effects: Dynamic Response Mechanisms

This article presents analyses of select experiments from a comprehensive geotechnical centrifuge program to investigate topographic effects in single-sided slopes. A unique benefit of centrifuge modeling is that it provides high-resolution measurements of a thoroughly characterized site while fully preserving physical processes. The analyses were performed in the time and time-frequency domains to investigate mechanisms that produced the topographic effects. The results indicate that resonance at the slope's topographic frequency is the principal driver of topographic effects. Site and topographic effects may combine at a slope crest to produce high levels of overall amplification. When topographic amplification occurs, the topographic zone of influence will vary depending on the ground-motion wavelength and the influence of phasing when multiple frequency components are present in the ground motion. Ground-motion complexities such as phase differences in response between a slope and the adjacent free field may serve to either amplify or de-amplify earthquake ground motion near a slope.

Automated summary

This article presents analyses of select experiments from a comprehensive geotechnical centrifuge program to investigate topographic effects in single-sided slopes. The results indicate that resonance at the slope's topographic frequency is the principal driver of topographic effects. When topographic amplification occurs, the topographic zone of influence will vary depending on the ground-motion wavelength and the influence of phasing when multiple frequency components are present in the ground motion.