Centrifuge Modeling of Seismic Performance of Reinforced Earth Structures - Reinforced Soil Engineering: Advances in Research and Practice - page 429

the larger density soil and 3-4% of the wall height for the small density soil, even
though the difference of the dry density was about 5%. However, it should be
noted that the large horizontal movement of the facing top was caused by both
deformation and horizontal translation of the reinforced zone. The cases with
lower density showed the larger horizontal translation (Fig. 8) but also showed
the larger increase in the residual tensile strains of geogrids as shown in Fig. 12,
which clearly implies that the geogrids functioned well in preventing the further
deformation of reinforced zone. From these observations it can be said that
because the large deformation or failure in the reinforced zone, as seen in
D20-150, was prevented, the large horizontal translation occurred instead for the
cases with the low density.

4 SUMMARY

This chapter has outlined the advantages and limitations of the centrifuge model
tests as a physical modeling on the performance of a reinforced soil structure.
Centrifuge model tests on the seismic performance of a geogrid reinforced
vertical soil wall done at the Tokyo Institute of Technology are also presented.
Because of the small size and high acceleration circumstances, the centrifuge
modeling technique has some limitations, both theoretically and technically,
which should be taken into account in interpreting the test results. However, as
the previous research-including the example presented here-has shown, the
centrifuge model tests can provide very useful information, such as failure and
deformation mechanisms and even more complicated interaction between soils
and reinforcement during earthquakes under well-controlled conditions. There-
fore, utilizing the advantages and compensating for the limitations by
cooperating with other techniques, such as relatively large-scale gravity
models, and analytical and numerical methods, the authors strongly believe that
centrifuge modeling will be able to contribute to the further development of
technology for earth reinforcement.

REFERENCES

MD Bolton, PLR Pang. Collapse limit state of reinforced earth retaining walls.

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Z Cai, RJ Bathurst. Seismic-induced permanent displacement of geosynthetic-reinforced
segmental retaining walls. Can. Geotechnical J. 33: 937-955, 1996.
MCR Davies, AM Jones. Stability of a steep excavation retained by soil nails. Proc.
Centrifuge 98(1): 773-778, 1998, Tokyo, Balkema.