Discrete element modeling of polyurethane-stabilized ballast under monotonic and cyclic triaxial loading

Abstract

A series of triaxial tests were conducted using the discrete element method to investigate the shear strength and deformation of the polyurethane-stabilized ballast with different dosages of polyurethane binder. The results show: The shear strength and Poisson’s ratio of the polyurethane-stabilized ballast increase with the dosage of polyurethane binder. The cohesion and internal friction angle of the polyurethane-stabilized ballast improve linearly with the increase of the polyurethane dosage. The deformation of the polyurethane-stabilized ballast also increases with the loading frequency while the deformation almost keeps stable after 40 Hz. The deformation of the polyurethane-stabilized ballast increases with the loading amplitude. The plastic collapse of the polyurethane-stabilized ballast with a lower polyurethane dosage occurs under a higher loading amplitude. Compared with the loading frequency, the loading amplitude has a more significant effect on the deformation of the polyurethane-stabilized ballast. The hoop effect exists in the polyurethane-stabilized ballast and the lateral expansion is constrained. The hoop effect is strengthened with the increase of the polyurethane dosage.