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Soil Nailing is
a procedure to reinforce and strengthen ground adjacent to an
excavation by installing closely spaced steel bars, called
"nails", as construction proceeds from the top down. The
process is effective in cohesive soil, broken rock, shale, or mixed
face conditions.
The technique permits flexibility to conform
to a variety of geometric shapes to meet specific site needs.
Spacing, placement angle and nail length can be varied to meet
almost any site-specific conditions such as easement or utility
location problems.
Excavation: Benches are cut
in lifts of typically 4-6 feet.
Nails: Holes are drilled into the excavated face.
Each drill hole is filled with cement grout and a nail is inserted.
The grout binds the nail to the surrounding soil and provides
corrosion protection. A steel plate attached to the protruding end
of each nail helps transfer forces from the wall to the nail and
soil.
Drainage: Horizontal and vertical drain strips are
installed onto the face to eliminate hydrostatic pressure and
control seepage.
Facing: A facing, constructed from shotcrete
reinforced by welded wire mesh or reinforcing bar mats, provides
structural integrity. The shotcrete can be smooth troweled for a
finished appearance or sculptured for an architectural look.
Continuing Construction: After each lift is
completed, excavation continues to the next bench and the process is
repeated to completion.
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With the right soil and site conditions,
a rapid and economical means of constructing earth retention
support systems and retaining walls.
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Allows foundation construction in limited
areas.
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Works through different soil strata.
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Constructed from the top down.
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Shorter drill holes.
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Smaller diameter bars at shorter lengths.
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Retaining walls are secured laterally
into the soil, eliminating piles and foundation footers.
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Excavation for the building and wall
construction can proceed simutaneously, saving schedule time.
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Not prestressed, saving labor costs and
time.
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Grouting only once is required, saving
time and labor.
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Requires only cohesive soil or broken
rock, does not need to be anchored in competent rock.
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Drainage system included eliminates
hydrostatic forces on facing.
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Hard face shotcrete is applied and can be
finish-troweled.
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Forming and placing concrete wall not
necessary, saving time, materials, labor.
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Soft facing can be applied for soil retention or
slope protection.
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