Geotechnical Considerations in Design and Construction of North Commuter Parkway, Saskatoon SK

This case history reviews geotechnical conditions and design of the North Commuter Parkway
(NCP) roadways and bridge crossing of the South Saskatchewan River at Saskatoon SK.
The geotechnical investigation of the NCP crossing identified complex geotechnical conditions
in both the river valley and on the upland. The site was located within the ancestral Glacial
Lake Saskatchewan, a proglacial lake that deposited variable depths of interbedded silt, sand
and highly plastic clay. Development of the river channel had eroded much of the lacustrine
sediments and underlying till leaving an eroded till landform with clay remnants on one side of
the valley and lacustrine sediments on the other. This varying morphology presented highly
variable geotechnical conditions with significant design challenges. Groundwater conditions
were controlled by regional aquifers that underlay the entire project area in addition to local
unconfined aquifers that were also addressed.

This paper presents the geotechnical design issues that were encountered in constructing the
roadways and valley crossing. It addresses geotechnical conditions, foundation design,
materials selection, groundwater control and construction issues that were addressed to
successfully deliver this P3 project that is scheduled for completion in 2018.