Doublestar Drilling’s construction of the third row of four temporary tieback anchors for a secant pile wall in January 2016. A total of 422
anchors were required for the design to reach an excavation depth of 15 metres.
tested to 200 per cent of the working loads were required at
each level of the wall due to the varying soil conditions, water
table and pressures.
“The average drilled depth for the anchors was 14 metres,
and all anchors were required to be post grouted multiple
times,” said Baldwin. “Two of Doublestar’s Davey Kent 725
drill rigs were used to drill the anchors. Air rotary drilling
with a downhole hammer was required for the majority of
the anchors.”
While Doublestar’s role in this mega project is certainly
impressive, it was definitely not without its challenges.
“The drilling specifications required zero soil loss to
prevent settlement of adjacent structures,” said Baldwin.
CONTINUED ON PAGE 42
PROJECT SPOTLIGHT
Doublestar Drilling’s Liebherr LB36 and LB28 drilling two of 452 one-metre-diameter, 19-metre-deep piles. Rock augers and segmental
casing were required for the entire depth in the construction of a secant pile wall.
40 Q2 2016 www.pilingcanada.ca
/www.pilingcanada.ca
