Numerical Evaluation of Constitutive Soil Models for Cyclic Soil–Structure Interaction in Integral Abutment Bridges

The accurate representation of backfill soil behaviour is a critical step in Finite Element (FE) analysis of Integral Abutment Bridges (IABs) subjected to thermally induced cyclic loading. This paper focuses on the evaluation and selection of a constitutive model, out of those commonly available in geotechnical FE packages, suitable for this purpose. Hardin–Drnevich (HD), General Quadratic/Hyperbolic Shear (GQHS), Hardening Soil (HS) including its extension to consider the small-strain stiffness (HSS), and the University of British Columbia (UBC) sand model were first assessed through simulating drained cyclic simple shear element tests. The results indicated that the UBC model captured key aspects of cyclic soil response more realistically than the other formulations. The HS model was also carried forward to the next stage due to its widespread use in soil–structure interaction analysis. Both models were then examined in a boundary value verification study, where numerical simulations were compared against published experimental results. The verification demonstrated that although both models captured the overall soil–abutment response, the UBC model provided superior agreement with experimental measurements, particularly in terms of passive pressure build-up with cycles. The study concludes that the UBC model offers the most reliable constitutive framework for FE simulation of IAB backfills under cyclic thermal loading.