Elastic-Viscoplastic Soil Constitutive Model for Simulation of Barrier Piles under Vehicle Crash Impact

The nonlinear dynamic interaction between soil and pile is a crucial factor in evaluating the performance of roadside piled-barrier systems during vehicle collisions. Previous studies have focused primarily on the structural aspects of these systems in numerical crash test models, and less attention has been given to the influence of soil on barrier performance. Existing soil models in LS-DYNA often exhibit overly stiff or overly soft behavior in road safety applications. To achieve a more reliable and optimal design of barrier piles subjected to impact loads, there is a need for advanced soil constitutive models to better capture nonlinear pile–soil interactions. We introduce a modified soil model named the damage–viscoplastic impact (DVP-Impact) model. This nonlinear soil constitutive model was developed with a small number of parameters requiring calibration, and can address the current gap in existing models, capturing strain softening and strain rate effects, which are critical in the modeling of soil–pile behavior in a vehicular impact scenario. The model was calibrated and validated at the element-scale using several triaxial experimental data, and at full-scale using real crash test data. We implemented the (proposed) DVP-Impact soil model in full-scale crash simulations using LS-DYNA, and then evaluated the model against other competing soil models. The results demonstrated the superiority of the DVP-Impact soil model for vehicular impact scenarios involving soil–pile interaction.