Underground Construction - August 2018 - 19

ing system and Tulsa Rig Iron
TT660 mud pump.
Solids and excess drilling
fluids were excavated utilizing
a trackhoe, and hauled away in
dump trucks. Thick excess drilling fluids were removed with a
Vactor vacuum excavator. Thin
excess drilling fluids were vacuum excavated with an 80BBL
vacuum truck.
One of the benefits of using
the hybrid fusible PVC, said
Meadows, was being able to
install pipe in a smaller reamed
hole than would have been required with HDPE pipe.
"A 9 7/8-inch pilot hole was
completed for each of the bores
and then 26-, 38- and 54-inch
ream passes were completed,"
he said. "A 48-inch swab was
completed and then the pipe
was pulled with a 48-inch tapered barrel reamer.
"The 20,000-plus psi granite
was encountered on the first
762-foot bore, and the hole
openers were changed from
mill tooth to TCI in order to
cut the rock."

Meadows said the three installations went smoothly considering the freezing weather
conditions that required overnight circulation and other winter-weather precautions.
Return mud lines were run
from the exit ends of the bores
back to the mud cleaning system
to help lessen the impact in the
neighborhoods, by pumping returns rather than driving vacuum trucks back and forth all day.
Four- and six-inch HDPE lines
were bored in when needed.
The two shorter bores were
fused into one string, and a
mid-fuse was necessary in the
long one. All pipe was placed
on rollers and in pipe cradles
during pull-back operations.

Fusion
"The fusing process for PVC is
the same as with HDPE, but is
specific to the PVC material,"
Meadows explained. "Garney
Construction handled the pipe
during the fusion and pull-back
operations, completed all HDD
tie-ins, and handled the open

cut portion of the project."
Meadows said the 1,712-foot
bore took about eight hours to
pull because a mid-fuse was required. The other two bores each
were pulled in four to five hours.
Rig breakdown and demobilization required one week.
The project was constructed and completed in summer
2017. All pipeline segments, including the three, long HDD installations, were pressure tested
to 150 psi for two hours, and
the line was placed into service.
Reflecting on the project,
Meadows said several factors
contributed to the successful
installation of the trenchless
segments.
"Global Underground," he
said, "teamed with two engineering firms to complete the
design profiles and HDD calculations to insure all aspects of
these crossings were discovered
and evaluated.
"Communication and teamwork between the owner,
general contractor, engineer
and Global Underground were

the key reasons that this project was successful. All parties
involved had the same goal in
mind. Whenever potential issues were discovered, the team
worked together to come up
with solutions."
Based in Colorado Springs,
Colo., Global Underground provides underground utility construction to a broad range of
clients utilizing open-cut construction, HDD, pipe bursting
and hydro excavation methods.
FOR MORE INFO:
Burns and McDonnell Engineering,
(713) 622-0227, burnsmcd.com
Garney Construction,
(303) 791-3600, garney.com
Underground Solutions,
(858) 679- 9551, aegion.com
Global Underground Corp.,
(719) 471-7414, globalug.com
American Augers, (800) 324-4930,
americanaugers.com
Vermeer Corp.,
(888) 8370-6337, Vermeer.com
Tulsa Rig Iron, (918) 321-3330,
tulsarigiron.com
Vactor, (815) 672-3171, vactor.com
UConOnline.com | AUGUST 2018

http://www.burnsmcd.com http://www.garney.com http://www.aegion.com http://www.globalug.com http://www.americanaugers.com http://www.Vermeer.com http://www.tulsarigiron.com http://www.vactor.com http://www.UConOnline.com

Underground Construction - August 2018

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