CLIENT: PCL Solar Constructors Canada Inc.
PROJECT DESCRIPTION:
Forty Mile Solar Project – Forty Mile County No. 8, Alberta. PRI completed geotechnical investigation, field and laboratory testing, helical pile probing, pre-production axial and lateral load testing, and foundation design recommendations for an approximately 220 MWAC PV ground-mount solar facility located on agricultural land near Bow Island, Alberta.
CHALLENGE:
The project required a practical foundation design for a large fixed-tilt racking system across a broad rural site with variable glacial till soils, potential cobbles/boulders, frost uplift considerations, corrosive soil conditions, wetland access constraints, and the need to confirm pile performance prior to production installation.
APPROACH:
PRI advanced a comprehensive subsurface investigation consisting of 44 boreholes, 14 test pits, piezometer installations, field electrical resistivity testing, and laboratory testing including grain size, Atterberg limits, Proctor, corrosivity, thermal resistivity, CBR, unconfined compressive strength, and hydraulic conductivity testing. PRI also completed 2,431 helical probes, installed 130 axial test piles and 35 lateral test piles, and used the results to develop site-specific helical pile design recommendations.
OUTCOME:
PRI provided design recommendations for the solar racking foundations, including site-specific torque/capacity relationships, frost uplift considerations, lateral capacity assessment, corrosion design considerations, production testing requirements, and construction recommendations. The testing confirmed that helical piles were a viable preferred foundation option for much of the site, with additional recommendations for areas not accessible during the investigation, including designated wetland areas.