3.6
FILL PLACEMENT
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NOTE: Subparagraph "c." below - Studies have
documented rubber tired heavy equipment traveling on
geogrids with minimal or no damage. However, it is
regarded as poor practice and usually unnecessary.
Problematic conditions include coarse crushed gravel
and coated geogrids. The intent of the
specification is to minimize equipment on the
geogrid so that it occurs only when necessary.
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a. Fill placement, including drainage aggregate, shall be completed to
the top of each course of facing blocks prior to stacking the
subsequent course of blocks.
b. Reinforced fill shall be placed from the wall back toward the fill
area to ensure that the reinforcement remains taut. Fill shall be
placed, spread, and compacted in such manner that minimizes the
development of wrinkles in or movement of the reinforcement.
c. A minimum fill thickness of 150 mm 6 inches is required prior to
operation of vehicles over the reinforcement. Sudden braking and sharp
turning shall be avoided. Tracked equipment shall not turn within the
reinforced fill zone to prevent tracks from displacing the fill and
damaging the reinforcement. Construction equipment shall not be
operated directly upon the reinforcement as part of the planned
construction sequence. Rubber tired equipment may operate directly on
the reinforcement if: the Contractor submits information documenting
testing of equipment operating on a similar geogrid product on similar
soils, the travel is infrequent, equipment travels slow, turning is
minimized, and no damage or displacement to the reinforcement is
observed.
d. Drainage aggregate shall be placed and tamped directly behind,
between, and within the cells of the facing units. Compaction of the
drainage aggregate shall be achieved by at least two passes on each
lift with a vibratory plate compactor. Care shall be taken not to
contact or chip the blocks with the compactor. Aggregate placed within
the block cores and recesses shall be compacted by hand tamping and
rodding.
e. At the end of each day, the Contractor shall slope the last lift of
fill away from the wall in a manner that will allow drainage and direct
runoff away from the wall face.
3.7
COMPACTION
Fill shall not be placed on surfaces that contain mud, frost, organic
soils, fill soils that have not met compaction requirements, or where the
Contracting Officer determines that unsatisfactory material remains in or
under the fill. Fill shall be spread and compacted in lifts not exceeding
the height of one course of blocks.
3.7.1
Degree of Compaction
Degree of compaction required is expressed as a percentage of the maximum
density obtained by the test procedure presented in ASTM D 698. The
SECTION 02832
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