WELL FOUNDED: Completing Geotechnical Investigation and Foundation Design in Tandem with Construction on a Challenging 310-Mile Canadian Transmission Line-PPT Presentation

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The Fort McMurray West project involved constructing 500 km (310 miles) of 500 kV transmission line and a substation across northern Alberta, with 1,368 structure locations. Limited early geotechnical data, difficult access through boggy and peaty terrain, and a compressed schedule meant investigation and foundation construction had to proceed concurrently.<br /><br />The team used a four-stage design approach: desktop studies to identify likely ground conditions; development of foundation options for different soils and structure types; preliminary foundation selection at each location using geological mapping; and in-construction investigations to confirm or revise designs. The desktop study drew on geological maps, borehole records, reports, laboratory results, and local expertise to define soil groups and subsurface profiles. Foundation options included driven and helical piles, drilled shafts, micropiles, shallow footings, and anchors.<br /><br />Geotechnical crews worked behind clearing crews, using multiple rigs to investigate sites as construction advanced. Borings, sampling, and penetration-test results informed final designs. At the Lesser Slave River, investigations identified soft clay and prompted development of additional soil profiles and revised helical-pile designs. Helical piles enabled faster installation and simpler field extensions than the original driven-pile designs.<br /><br />The project demonstrated the value of combining early regional geological assessment with flexible foundation options and timely field investigation. Construction was completed in 14 months—four months ahead of schedule.

Keywords

Fort McMurray West

transmission line

geotechnical investigation

foundation design

helical piles

drilled shafts

boggy terrain

soil profiles

construction schedule

northern Alberta