31 Jan 96
body of the PowerPunchTM is retracted and separated from the
rods. The body forms a seal above the screen.
- The other way is to screw an expendable metal tip into the
end of a slotted PVC screen. The 12.7 mm PVC is placed through
the center of the 44.4 mm O.D. rods. As the screen is pushed to
depth additional screen or casing is added along with direct push
pipes. At the desired depth, the push rods are retracted leaving
the metal tip, PVC screen and risers in place. The 38.1 mm I.D.
PVC is emplaced in a similar way, but the PVC is placed over,
rather than inside, the 36.6 mm push rods.
(d) Sampling from well points is more desirable from a
production standpoint; if the truck is tied up in ground water
sample collection (e.g., with a HydroPunchTM), it is not
available to collect sensor data at other locations. Depending
on the number of analytes and the permeability of the formation,
d. Grouting Capabilities: Cone penetrometer push holes are
grouted through the tip of the probe as the rods are withdrawn
from the push hole.
A grout consisting of microfine cement or
portland cement, water, and bentonite (if desired) is mixed. The
grout is pumped to the probe tip via a 9.5 mm diameter TeflonTM
tube contained in the umbilical cord. The grout forces a small
expendable metal tip from the end of the probe. Holes made to
collect physical samples are grouted after the rods are retracted
since sampling devices do not have grouting capability.
e. Survey: SCAPS is equipped with either a Sokkia Total
Station electronic distance measurement (EDM) survey instrument
instrument can provide readings in both vertical and horizontal
directions. A three prism mirror configuration yields a range of
1067 meters. An electronic field notebook is attached for data
collection. Data are downloaded into a software program that
renders drawings of survey points. GPS equipment provides
differential location accuracies of 30 to 50 mm (horizontal and
vertical) and automatic annotation of the boring data file with
f. New Sensors: The SCAPS program continues to develop new
sensors and samplers to expand and enhance system capabilities.
Sensors currently being field tested include a sensor for
nitrate-based explosives, electrochemical sensing of volatile
organic compounds (VOCs), and a spectral gamma sensor for
undergoing field testing include a multi-port soil gas sampler,