level, or where turf can not be established.
Department of Transportation specifications for road
base aggregate have been used, such as ASTM D 1241,
Gradation B.
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Aggregate for filling the voids in the block shall meet the requirements of
[_____].
2.4.2
Topsoil and Seed
Topsoil for filling the voids in the block and seed for turf establishment
shall meet the requirements of Section 02921 SEEDING.
PART 3
EXECUTION
3.1
SUBGRADE PREPARATION
The ACB revetment shall be placed on undisturbed native soils, or
acceptably placed and compacted fill. The ACB shall not be placed on
surfaces that contain mud, frost, organic soils, embankment that has not
met compaction requirements, or where the Contracting Officer determines
that unsatisfactory material remains in or under the subgrade.
3.1.1
Clearing
All vegetation shall be completely removed as specified in Section [02300
EARTHWORK] [02231 CLEARING AND GRUBBING]. Remaining roots from trees and
brush shall be removed to a depth of 0.3 meters 1 foot below the subgrade
surface. Loose roots and twigs, turf clods, stones larger than 12 mm 1/2
inch diameter, and other debris shall be raked and removed from the final
surface. Rills and gullies from erosion shall be corrected.
3.1.2
Bank Grading
Grading shall be finished to a smooth surface, typical of that obtainable
with a dozer and blade. A rough surface typically obtained with a backhoe
or dragline will not be acceptable, except when ACB placement in water is
shown on the drawings or approved by the Contracting Officer. [When natural
shorelines require grading in preparation for ACB installation, the bank
stratification shall be observed and documented in daily Contractor Quality
Control reports. Grading practices shall avoid spreading fine grained
soils over more pervious soils, particularly near the toe of slopes. If
inadequate material is available to comply with this requirement, the
Contracting Officer shall be notified.].
3.1.3
Compaction and Subgrade Finishing
[Fill soils shall be compacted to the specified density in Section 02300
EARTHWORK.] Incidental grading (where embankment is not otherwise
specified) shall be compacted by heavy equipment or by tamping with a
bucket to a density characteristic of the surrounding soils. The final
surfaces accessible by compaction equipment shall be compacted with a
smooth drum roller or vibratory plate tamper until there is no further
evidence of consolidation. Where slopes limit operation of compaction
equipment, the final surface shall be back-dragged to a dense smooth
surface with bladed equipment. Localized loose or soft zones shall be
corrected.
SECTION 02382
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