Application of an Advanced Constitutive Model for Shakedown Analysis in Unbound Pavements

This study uses a cutting-edge constitutive model for analysing shakedown phenomena in unsaturated granular soils commonly used in lightly and moderately trafficked pavements. The primary source of structural support in these pavements comes from granular soils used in the subbase and the subgrade soil. This highlights the crucial role of accurately evaluating their mechanical properties for optimum design and use of materials. Our model successfully captures material kinematic hardening with memory and provides more accurate simulations of the hydro-mechanical shakedown in these soils under millions of load cycles. The model also addresses some key computational challenges associated with a large number of load cycles, such as potential numerical instability and a significant loss of accuracy. The model’s capabilities are showcased, highlighting its proficiency in simulating soil plastic deformations. This is particularly demonstrated in a novel laboratory test, the constant radial stiffness triaxial (CRST) test, designed to mimic traffic loading on unbound pavements. It is argued that this test better simulates the stress path encountered by road materials under moving traffic loads in the field than the traditional repeated load triaxial (RLT) test.