Macro and micro analyses of static and dynamic shear characteristics of geogrid and rubber–sand mixture interface

Abstract

A rubber–sand mixture (RSM) can be used as a novel type of geotechnical material in reinforced roadbeds and other projects owing to its being elastic and environment friendly. To explore the static and dynamic shear characteristics of the geogrid and RSM interface, monotonic direct shear (MDS), cyclic direct shear (CDS), and post-cyclic monotonic direct shear (PCDS) experiments were performed in this study. The effects of rubber content (χ) and particle size ratio (r) on the interface shear characteristics were studied. A dynamic model of the rubber–sand mixture was established using PFC3D, and mesoscopic analysis of the cyclic shear process was conducted. The results of the CDS experiments indicated that the peak shear stress with χ = 10 % was the largest. The peak strength and residual strength of PCDS were larger than those of MDS under the same χ and r. After cyclic shearing, the interface apparent cohesion of various rubber contents and particle size ratios increased by 78 % ∼ 172 %. During cyclic shearing, the porosity and particle energy in the shear box changed periodically, and the porosity near the interface was slightly higher than that in the other areas. The kinetic energy of the particles was closely related to the shear displacement.