Post-Earthquake Investigation of Several Geosynthetic Reinforced Soil Retaining Walls and Slopes During Ji-Ji Earthquake of Taiwan - Reinforced Soil Engineering: Advances in Research and Practice - page 297

Figure 7 Ta Kung Roadway 129 geosynthetic reinforced soil retaining wall: (a) front
view of collapsed section; (b) side view; (c) backfill soil; (d) geogrid reinforcement; (e)
block with the connection pins.
geosynthetic reinforced retaining wall was found (Fig. 7). The wall was
constructed with four-block reinforcement spacing. Figure 7b shows the largely
deformed portion of the wall. The modular blocks were buried under the backfill
soil (Fig. 7c). The backfill material is a silty sand. A polyester geogrid was used
(Fig. 7d). Figure 7e shows the block used as facing for the reinforced soil
retaining wall.
Figure 7b shows that the largest horizontal displacement was at a height of
8 blocks (1.6m) from the bottom of the wall. This point of maximum
displacement varied along the length of the wall. However, failure could be
initiated from the bottom of the wall, at the region where the blocks totally
collapsed, because of excessive displacement. A major crack was observed at a
distance 5.6m behind the wall. A minor crack was also formed at about 2.5m
behind the wall, which corresponded to the length of geogrid reinforcement. In
Taiwan, the length of geosynthetic reinforcement is typically selected as 70% of
the wall height for modular block reinforced soil retaining walls.
Note also that the transverse rib of the geogrid reinforcement was torn at the
location of the connection pins (Fig. 7d). Some of the pins were bent and
yielded because of the movement of the blocks. The results indicated that