Conventionally, the use of poor draining backfills for reinforced
soil structures has been avoided whenever possible. However,
the use of poor draining backfills can be considered with
Anchored Earth wall system because of the enhancement in pullout
resistance provided by the anchor blocks.
In a housing project in Kulim, Anchored Earth
system was adopted to reinforce poor draining backfill. Due
to the JKR road reserve boundary, Anchored Earth wall was
constructed to retain a 3m high slope upon which the housing
projectwas situated. The backfill material available on site
comprised cohesive frictional residual soil with 36% silt
and clay. This backfill material, though makes for poor draining,
complied to the specification stipulated for use with Anchored
Earth wall. Dissipation of pore water pressure in the backfill
was provided for through drainage blanket incorporated behind
the facing panels. French drains were also incorporated at
several locations along the height of wall. These drains were
laid perpendicularly to the facing at 3m horizontal spacing.
The construction of the whole wall extended
170m long with average height of 4.5m. On site pullout tests
on the reinforcing elements and vertical checks on the wall
were carried out which showed that the wall is in excellent
condition.
Apart from providing structurally stable
and aesthetically pleasing structure, the use of Anchored
Earth wall in this housing project with poor draining backfill
resulted in tremendous cost savings.
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