Evaluation of seismic efficiency of geosynthetic-reinforced soil walls under actual earthquakes

Seismic design methods for geosynthetic-reinforced soil walls are based on the seismic coefficient method from laboratory experiments. However, because soil structures constructed by such design methods had not yet experienced actual earthquakes, applicability of such design methods to actual soil structures was yet to be seen. Collin, et al. (1992) reported the survey results of five reinforced soil structures subjected to the Loma Prieta earthquake (1989) in San Francisco. In 1993, the Kushiro offshore earthquake struck the eastern region of the Hokkaido island of Japan, and there was a geosynthetic-reinforced soil wall in the earthquake-struck region. In both the earthquakes, there occurred no damage to the reinforced soil structures surveyed, demonstrating the abilities of these structures to withstand heavy earthquakes. The purpose of this paper is to evaluate, based on the two actual earthquakes, the seismic design methods proposed in Japan.