Underground Construction - September 2019 - 23

Experience
Superior
Performance
"The steel pipe," continued Richey, "is pushed with material
inside the pipe and cleaned out with machine augers. This proceeded in 20-foot sections that are welded together to extend a 36-foot
pipe and exterior grout tube, and once again an auger removed
materials that were generated." Material was removed with the
Link Belt 350X3 excavator and loaded into dump trucks and hauled
to a local permitted fill site.
Construction of the canopy continued from the bottom, alternating sides to gradually change alignment to achieve the desired arch
formation. Once the canopy arch was complete, the crew then used
cutting torches to cut holes through adjoining pipes, bolting them
together with hardened bolts.

Grout
After bolting was completed, exterior tubes were grouted with
a neat cement grout. The grout tube was withdrawn when grout
reached specified quantities.
"Grouting," Richey said, "seals any small openings between
canopy tubes. This step is repeated until all seams between pipes
have been grouted."
When a grout seal was in place, the material inside the canopy
was excavated to the specified elevation. Material was removed
inside the canopy system with a Takauchi 135 mini excavator,
loaded into a Marooka wide-track haul truck, then transferred
to dump trucks with the LinkBelt excavator and hauled to the
permitted fill sites.
The final tunnel lining system was a "U"-shaped rib and lagging
tunnel, approximately 140 feet long. The rib and lagging system
consisted of W8x58 ribs at 4-foot centers with fiber-reinforced
shotcrete in-between the bays. The invert of the tunnel consisted of
8x58 floor struts at 4-foot centers with fiber-reinforced shotcrete
to provide a flat bottom.
"The final step," said Richey, "was the installation of a gravel
stream bottom with fish rock and tree structures added to make it
a suitable fish habitat, and the diverted stream reintroduced to the
new alignment for the new fish passage."
Installation of the canopy was completed in six weeks. The total
project was finished in five months.
Based in Tillamook, OR, LRL Construction specialties include
tunnel rehabilitation and enlargement, soil stabilization, rockfall
mitigation, shaft construction, shotcrete, culvert installation,
soil nail and rock bolting and tunnel assessment. The company is
known for fast response to natural and man-caused disasters and
most types of construction emergencies. *
FOR MORE INFORMATION:
LRL Construction, (503) 842-5520, lrlconstruction.com
American Augers, (800) 324-4930, americanaugers.com
Akkerman Inc., (800) 533-0386, akkerman.com

XTR Reamers
Inrock's XTR reamers provide a modular,
re-usable platform in sizes ranging from 28"
to 60" and accept INROCK's proprietary Milled
Tooth, Standard TCI, or Premium TCI cutters
specifically designed for HDD. XTR provides
flexibility and consistent performance
to get the job done.

For more information,
call 1 (877) 2 INROCK or visit www.inrock.com
UConOnline.com | SEPTEMBER 2019

http://www.lrlconstruction.com http://www.americanaugers.com http://www.inrock.com http://www.akkerman.com http://www.UConOnline.com

Underground Construction - September 2019

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