Figure 9b also demonstrated that the amplification factor of geocell-RS RW in the reinforced
backfill zone was lower than that of geogrid-RS RW before the value of base acceleration around 550
gal indicating a higher shear stiffness of geocell-RS RW due to the larger mobilization of tensile force
of geocell reinforcement. Note also that, the amplification factor increased suddenly at the base
acceleration of 400gal for geogird-RS RW and 550 gal for geocell-RS RW, respectively, which
suggested that the reinforcements at the top (i.e. Layer 10 shown in Figs. 3a and 4a)were pulled out
from backfill soil. Finally, by comparison of the amplification factors at the top of wall and at the
depth of 5 cm in the reinforced soil zone, it is found that the trends of amplification response were
similar but the latter showed a smaller value of amplification factor. This is indicative of a possible
phase difference in deformation-time response between the rigid wall facing and the backfill soil.