Failure pattern of models
Figure 6 shows the residual displacement of the wall and the residual deformation of the backfill,
which were observed at the end of the final shaking step. It can be seen that the predominant failure
type for all three cases was overturning, associated with some small component of sliding failure. For
the gravity-type RW, brittle failure occurred during the base acceleration of 488 gal and a single failure
plane was formed starting from the heel of the wall. For the geogrid-RS RW and geocell-RS RW,
similar ductile failure patterns were observed during the base acceleration of 790 gal and 877 gal,
respectively, which indicated that geocell-RS RW has a higher seismic performance than geogrid-RS
RW as well as gravity-type RW. In addition, the reinforced backfill suffered simple shear deformation
along horizontal planes (Watanabe et al., 2003; Nakajima et al., 2010), and two differently inclined
failure planes developed simultaneously in the unreinforced backfill zone while the development of
the failure planes may originated from the position between Layer 1 and Layer 2 (shown in Figs. 3a,
4a and 6) not the bottom of the reinforced wedge, indicating that the bottom layer of reinforcements
may restricted the sliding of the wall, which will be discussed hereafter.