U.K. Case Study: Bluewater Retail and Leisure Destination Reinforced Soil Slopes to Form Steep-Sided New Lakes - Reinforced Soil Engineering: Advances in Research and Practice - page 139

For Lake 1, the critical condition for internal stability was identified as the
completed structure fully landscaped under the rapid draw-down condition with
the lake empty (perhaps during a future maintenance operation) and the backfill
behind the reinforced soil block fully saturated. A typical reinforcement layout
for the north side of Lake 1 is shown in Fig. 6. The maximum vertical
reinforcement spacing was set at 60 cm.
The road embankment, which is not featured in this paper, formed part of a
later contract and was also constructed using Tensar uniaxial HDPE
reinforcement and a 60

face, formed by wrapping grids around permanent
filled bag formers, which were subsequently planted.

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2.4 Face Detail

The face of the reinforced slopes had to be relatively inexpensive while
possessing high durability and damage resistance. The engineer ruled out a
proprietary segmental concrete block face on the grounds of cost, and instead
selected a geogrid wraparound face. With this detail, the horizontal
reinforcement layers are extended up the temporarily supported face of the fill
and then returned back horizontally and connected with a full-strength joint to the
next layer of reinforcement. There was sufficient information on the durability of
the specified grids to satisfy long-term serviceability questions (Wrigley, 1987).
The face also had to remain permeable and retain the silty sand fill.
Attention was therefore focused on the selection of a geotextile filter to line the
wraparound face. It was recognized that any damage or malfunction of this
geotextile could lead to a steady washout of fines and ultimately to collapse.

Figure 6 Typical reinforcement layout.