Optimised Calibration Algorithm of a Bounding Surface Model for Coarse-Grained Soils

Several constitutive models have been developed over the years to capture the salient features of the undrained cyclic stress-strain response of sandy soils, that is of crucial interest for assessing the behaviour of geotechnical systems under seismic loading. Among them, the bounding surface plasticity theory turned out to be a valuable framework for reproducing the hardening soil response under both drained and undrained conditions. However, such models usually require a non-straightforward calibration of many parameters, employing also trial-and-error procedures that inhibit the physical meaning of the parameters and their eventual correlation. In this view, the present study proposes an optimised procedure for calibrating the trial-and-error parameters of bounding surface constitutive models for coarsegrained soils. The proposed approach is applied to a modified version of the model developed by Papadimitriou and Bouckovalas (2002), which was recently implemented in OpenSees by the Authors to investigate liquefaction-related phenomena. Based on the obtained results, a preliminary correlation between the critical parameters and a significant response quantity to identify liquefaction triggering is proposed with reference to a well-characterised soil. Consideratio