ABSTRACT
Recent earthquakes caused severe damage to the retaining walls of various castles in Japan. In this study, the authors describe this instrumentation, some numerical analyses and the results obtained so far. The site investigations clearly showed that river gravels were used as backfilling materials at the collapsed castle retaining walls. In this study, the authors have investigated the effect of the type of backfilling material on the seismic response and stability of the model castle retaining walls using a shaking table in the laboratory. In addition, a dynamic limiting equilibrium approach was used to investigate the responses and stability of the test results on the model castle retaining walls. The experiments and theoretical studies clearly showed that the type of backfilling material has a great effect on the dynamic response and seismic stability of the walls and the results clearly showed that the castle walls utilizing rounded river gravels as backfilling material are quite vulnerable to fail during great earthquakes. The authors would present the outcomes of the this unique experimental and analytical study and discuss their implications in practice.
