different subsoil conditions until a satisfactory load test has been
performed in that area.]
3.2.1
Casings Placement
Casings shall be approved by the Contracting Officer and shall be left in
place and filled with grout. The casing shall be rotated by the auger
drive unit or weighted or jetted to the required depth. After the casing
is in place, the casing and hole shall be cleared of water, sediment, and
debris prior to pouring the grout.
3.2.2
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NOTE: Delete the sentence in brackets when test
piles, load tests, and soil probes are not used.
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Except where auger withdrawal is required or directed by the Contracting
Officer, each pile hole shall be drilled and filled with grout in an
uninterrupted operation. Drill each pile hole to the required tip
elevation. [Should the required tip elevation shown on the drawings differ
from the calculated tip elevation, an adjustment in the contract
requirements will be made.] Advance the auger at a continuous rate which
prevents removal of excess soil. Stop rotation of auger after reaching the
required pile tip elevation.
3.2.3
Grouting and Auger Removal
At the start of pumping grout, raise the auger from 152 to 300 mm 6 to 12
inches and after grout pressure builds up, indicating discharge of grout,
redrill auger to the required tip elevation, and fill pile hole with grout
without interruption. When the auger is withdrawn to check the soil
profile, it shall be reinserted in the pile hole to the required tip
elevation and the pile hole then filled with grout without interruption.
Coordinate rate of grout injection and rate of auger removal from the soil
in such a manner as to maintain a positive pressure on the grout pressure
gauge. The gauge indicates the existence of a removing pressure on the
bottom of the augerflight. If the auger jumps upward during withdrawal, or
if the grouting process is interrupted, or if there is decreased grouting
pressure, reinsert it to the original tip elevation and decrease the rate
of withdrawal to prevent further jumping. The auger may rotate very slowly
during withdrawal. However, counterclockwise rotation is not permitted.
3.2.4
Pile Butts
Unless a permanent steel casing is provided as specified in paragraph
entitled "Casings," place a steel sleeve at top of pile to form the pile
butt. For pile cutoff above ground surface, the steel sleeve shall extend
from the pile cutoff elevation to a point not less than 305 mm one foot
below the ground surface. For pile cutoff at or below ground surface, the
steel sleeve shall extend from the ground surface to a point not less than
300 mm one foot below the pile cutoff elevation. Pump excess grout to
displace as much potential laitance as possible. Remove pile butt to
required cutoff elevation or to sound grout, whichever is lower.
3.2.5
Placement Tolerances
Locate piles where indicated.
The maximum permissible variation of the
SECTION 02465
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