Calibration of the Hardening Soil Small Strain Constitutive Model Parameters for Toronto Glacial Till

ABSTRACT: The Finch West Light Rail Transit infrastructure project proposed in Toronto requires construction of deep retaining walls with excavations into approximately 18m of glacial till of the Halton geologic unit, consisting of silty clay and sandy silt. An advanced finite element constitutive soil model, the PLAXIS Hardening Soil with Small Strain (HSs) model, was used to perform soil-structure interaction analysis. The model was calibrated with laboratory and field test data, which comprised isotropically consolidated, drained and undrained triaxial compression, oedometer, and geophysics. This study summarizes the range of HSs model input parameters that are applicable for the project geology. The HSs model predictions were validated using two methods: the model predicted undrained shear strength was found to be comparable with the TEXAM Pressuremeter field measurements, and the model predicted shoring wall deflections were found to be comparable to inclinometer data from a historical excavation in similar geology.