Recent Experiences of Reinforced Soil Retaining Structures in China - Reinforced Soil Engineering: Advances in Research and Practice - page 171

4.1.1 Design and Construction

The retaining wall is composed of three parts; concrete facing plate measuring
1.0

0.4m 2 , polypropylene webs with tensile strength of 4 kN per strip and
elongation of 2%; and backfill of collapsed soils.
The wall has a vertical face and a platform with a width of 1.4m at the
height of 17.2m. The design was based on the limit equilibrium method. The
subsoil was improved by three rows of piles, whose length was 4.5m, and the
sludge of the top subsoil with a depth of 1.5m was replaced by lime soil.
Considering the elongation of webs, the facing plate was constructed with initial
front slope 1:0.01 toward backfill. The sequence of compaction is from the
middle of webs to the ends, then to the facing plate. The range of 1.5m nearby the
plate was compacted by a small-sized compactor.

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4.1.2 Monitoring

4.1.2.1 Stress of Subsoil. Two rows of pressure cells were pre-
embedded on the top of the subsoil. The readings of pressure changed with
the height of the backfill (see Table 1). The pressures at the same height of
backfill were different. It is due to different positions and good or poor
contact with soils.
When the depth of the backfill was more than 22m, the pressure readings
were unchanged.

4.1.2.2 Lateral Deformation of Facing Plate. The lateral deformation
was monitored by the attaching strain gauges. Results show that the deformations
of plates don't have a regular pattern at the construction period, depending on the
looseness or tautness of webs and compaction. When a load on top of the backfill
was increased, the maximum lateral deformation appeared in the middle of wall
height (H/2) toward outside. The deformation of the top plate was slightly toward
the backfill. When the load decreased, the deformation could not be restored.

Table 1 Stress of Subsoil

Depth of
backfill (m)

Pressure
(kPa)

12 120-390

19 204-420

22 380-490