Doublestar Drilling’s Davey Kent 725 drilling the fourth row of temporary tieback anchors for a secant pile wall construction
in February 2016. Air rotary drilling with a downhole hammer was required for the majority of the anchors.
“The 15-metre deep excavation was designed with 19-metre
secant piles, which was uniquely incorporated into the structure’s
permanent engineered flood mitigation system,” said
Nick Baldwin, director of projects for Doublestar Drilling.
“The parkade structure is located only metres away from
the banks of the Bow River, and is four levels below the river
elevation. The secant piles are 1 metre in diameter and interlocked
20 cm to provide decreased permeability of ground
water. Full-length segmental casing was used for the entire
depth due to the groundwater and heaving soil conditions
due to the saturated silts. The 323 infill piles and 129 soldier
piles were installed by Doublestar’s Liebherr LB36 and
Liebherr LB28 drill rigs.”
Additionally, 422 temporary tieback anchors, located
along four rows, were required to support the secant piles.
Anchors were designed for working loads of 570kN and proof
loaded to 133 per cent of the design loads. Test anchors
CONTINUED ON PAGE 40
PROJECT SPOTLIGHT
“This area of the city has highly saturated silts due to the flow of subsurface
water that travels from the Elbow River to the Bow River, known as ‘the
channel.’ The channel has caused major issues with excavation projects in
the past due to loss of soil, resulting in settlement issues.”
– Nick Baldwin, Doublestar Drilling
38 Q2 2016 www.pilingcanada.ca
/www.pilingcanada.ca
