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 137

¼ ½ W cos a

þ P sin ð 10 8 þ a Þ tan 20 8 þ W sin a

FoS ð 4 Þ

P cos ð 10 8 þ a Þ

where FoS factor of safety against sliding over the lining system (i.e., the

resisting force divided by the sliding force). FoS for design was specified as 1.5
for the temporary condition and 2.0 for the completed works.
Checks were made for difficult lake conditions: Immediately after
construction, after surcharging with the highway embankment, and at final
handover. All possible combinations of external and lake water levels were
considered. Figure 4 shows the cross section through the north side of Lake 1 and
the particular loading condition found to be critical for sliding stability, that is,
the condition prior to the placement of landscaping fill and with the lake water
level lower than its final design level.
The width of the reinforced soil block is dimensioned to provide sufficient
weight (W) to satisfy FoS.
Lakes 1 and 2 were also checked for other external stability conditions,
including sliding over the reinforcement.

¼

2.3 Internal Stability of Reinforced Soil Block

The specialist designer's experience of other reinforced soil structures with a
similar geometry was that design principles based on the German Institut f¨r
Bautechnik (DIBt) would produce a stable and economical solution. Internal

Figure 4 Cross section through north side of Lake 1.