Geosynthetic solutions for road stabilization and railway ballast optimization over frost susceptible and expansive clays: A case study of the Cargill Canola processing facility

Abstract

The Cargill Canola processing facility, a $350 million project, began construction in July 2022 and is set to be operational in 2025. The site's geology primarily consists of fine-grained glaciolacustrine sediments, mainly silts and clays. A significant geotechnical challenge was the presence of a weak upper silty clay soil layer, approximately 10 metres thick, which was susceptible to frost heave during freezing temperatures and volumetric changes due to water exposure. Spring melt also raised concerns about excess water accumulation weakening the subgrade, leading to structural damage. The high plasticity index of the subgrade increased the potential for swelling in warmer conditions, complicating the design challenges during seasonal transitions. To address these issues, geosynthetics were employed. Three types were used: a moisture management woven geotextile to provide hydraulic and mechanical stabilization in the rail and road structures, an integrated high-modulus woven geotextile to provide ballast reinforcement, and a biaxial geogrid for base reinforcement in the access roads. The integrated high-modulus woven geotextile was also used in staging areas and gravel pavements to reduce the amount of granular base material required. This case study offers valuable insights for geosynthetic solutions in stabilizing roads and optimizing railway ballast over frost-susceptible and expansive clays. It demonstrates the effectiveness of geosynthetics in mitigating challenges posed by weak soils, frost susceptibility, and expansive clays, contributing to more resilient infrastructure designs.