Investigation of elastoplastic constitutive model of rubber-sand mixture

The rubber-sand mixture (RSM) has been extensively applied in the engineering construction as a lightweight filling material. However, the mechanical characteristics of RSMs are still not completely understood and the constitutive model used to simulate the RSMs by FEM analysis is also lacking. This study presents a newly developed constitutive model based on the critical state framework that describes the stress–strain relationship and dilatancy behavior of RSMs with different rubber contents. The relationship between rubber contents and critical state parameters was introduced in the established constitutive model. The comparisons of test results and model calculations show the RSM model can better capture the strain softening behavior, dilatancy characteristics and the critical state of RSMs. The RSM model was compiled by the user-defined material (UMAT) in ABAQUS and then utilized to simulate the triaxial tests. The developed RSM model is suitable for the triaxial compressive test using monotonic radial loading in triaxial space. The calculation results demonstrate the correctness and effectiveness of the developed model, which can be used as a reference in the engineering practice.