Slope Stabilization and Pathway Work
Doublestar Drilling considered all options to reduce the
environmental impact on this Calgary project
In November 2017, Pomerleau awarded Doublestar Drilling
(DSD) the Douglasdale-McKenzie Lake Slope Stabilization
& Pathway Project located in Calgary, Alta., on the banks
of the Bow River. DSD was responsible for supplying and
installing 236 cast-in-place (CIP) concrete piles, 234 rock
anchors, 225 micropiles, 800 m2 of shotcrete and the instal-lation
of geotechnical instruments: Slope Inclinometers and
CSL Tubes.
This diverse scope of work required an immense amount of
pre-project planning between DSD and Pomerleau to ensure
that the design requirements, safety and site specifications
were compliant with The City of Calgary Standards. Due to
the environmental sensitivity factors of this project, DSD took
every precaution available to guarantee that all risks were
mitigated to prevent any potential environmental impacts.
Equipped with special sound dampeners on the Kelly
bars and the engine silencer kits on the Liebherr drilling rigs,
noise levels were minimized for the surrounding residential
communities. It was critical to the design that the equip-ment
didn’t exceed 200 kilopascals of downward pressure
on the drilling platform. Therefore, DSD carefully chose their
Liebherr drill rigs and crawler crane to ensure this require-ment
was met throughout the project.
First, DSD completed the 165-millimetre-diameter micro-piles
that were installed in four months with a 32 mm DSI
threadbar using their Davey Kent 725 and Interoc AN150 drill
rigs. DSD equipped their rigs with solid stem and air rotary
tooling applications in order to complete approximately
3,465 metres of total drilled depths.
DSD selected the Liebherr LB-28 drill rigs to complete the
CIP piles due to their powerful torque and crowd capabili-ties,
eliminating any need for vibratory and/or slurry drilling
methods. Their Liebherr HS855 HD crawler crane was uti-lized
for lifting and tying cages onsite. In just over six months,
DSD’s piling crew completed the 236 914-mm-diameter CIP
piles to depths of 32 m and moved their focus to the remain-ing
rock anchors and shotcrete.
Prior to drilling, DSD completed pre-production rock
anchors, which were stressed up to 200 per cent of the design
load, to determine the remaining anchors’ design capacity
and validate the anchor bond parameters.
Going forward, all anchors are to be proof tested to 133
per cent of the design load of 650 kilonewtons and installed
with a 46-mm double corrosion protected threadbar. The
150-mm-diameter anchors are being installed to depths of 32
m which will be completed by DSD’s HUTTE HBR610 drill.
Currently, about 95 rock anchors have been completed and
DSD continues to prepare the installation of the remaining
anchors and shotcrete to complete this project on time and
on budget.
Submitted by Doublestar Drilling
GREAT CANADIAN PROJECTS
PHOTO COURTESY OF DOUBLESTAR DRILLING
PILING CANADA 31