Numerical modeling of scale load testing on spread footings in sandy soil: a comparative analysis of HSM and HYPO-Small models

Abstract This study critically evaluates the predictive performance of the Hardening Soil Model (HSM) and the Hypoplastic Model with small-strain stiffness (HYPO-Small) for simulating the behavior of shallow foundations on sandy soils subjected to vertical loading. Both models were rigorously calibrated using experimental data derived from site-specific and laboratory tests, particularly triaxial testing, ensuring a robust representation of the complex, nonlinear soil behavior under loading conditions. Model validation was carried out through controlled load tests, affirming their reliability in predicting real-world responses. The findings reveal that the HYPO-Small model is particularly effective in capturing the nonlinear and cyclic characteristics of soil behavior, excelling in the simulation of hysteresis effects and small-strain stiffness. These capabilities make it highly suitable for advanced analyses of soil-structure interactions under cyclic loading conditions. In contrast, the HSM provides more accurate predictions of initial stiffness and early-stage settlements, offering substantial value in the preliminary design phase of foundation systems. By rigorously validating both models through comprehensive numerical simulations, this study delineates their respective advantages and limitations, providing a clear framework for geotechnical engineers to select the most appropriate constitutive model for achieving optimized, efficient, and cost-effective foundation designs.