Large-Scale Reinforced Clay Walls Backfilled with Clay at Cheng Kung University - Reinforced Soil Engineering: Advances in Research and Practice - page 188

Plate 1 The completed NCKU walls.
3 CONSTRUCTION OF TEST EMBANKMENT
A24-m-long, 8-m-wide, and 1.0-m-high test embankment (Fig. 4) was constructed
at a port construction site about 20 km from the campus of NCKU using an alluvial
clay similar to that used for the NCKU reinforced walls. Prior to the construction,
in-lab compaction tests following the procedure of ASTM D698-91 were
performed to obtain the compaction curves for the clay. Different clod size
distributions were intentionally employed to study the effect of clod size of clay to
the compaction curves. Figure 5 shows that the result of compaction was
influenced by the size of clod to some extent. Sample 1 was obtained from the
standard sample preparation procedure. Larger clod sizes were introduced for
samples 2 and 3. It is seen that the samples with larger clod sizes tended to have
larger dry densities. However, it is seen from Fig. 5 that the soil sample with larger
clod size had a larger permeability coefficient. It is considered that a large clod size
might create interparticle planes to facilitate the seepage in the soil mass.
Saturated alluvial clay obtained from the construction site with natural
water content of about 22.5% was air-dried on-site for about 47 days. During the
air-drying process, the soil was disturbed thoroughly using a backhoe for three
times to speed up the drying process. The ready-for-use clay has typical clod size
distributions as shown in Fig. 6 and water contents between 7% and 9%. Soil was