Granular materials are usually used in low-traffic pavement structure as base layer or sub-base layer. The influence of fine content on permanent axial deformation behaviour is significant as well as the water content. This study aims to investigate the permanent axial deformation behaviour of the granular material under cyclic loading at various water contents and various fine contents. A triaxial apparatus is used to obtain permanent axial deformation on the samples prepared with the same dry density at different water contents between 7% and 11% and at different fine contents of 4%, 7.5% and 15.3%. The results show the significant influence of water content and fine content on permanent axial deformation behaviour. The permanent axial deformation increases with the increase of water content while the influence of fine content depends on the water sensitivity of fine particles and their initial water contents. The modified empirical-analytical models are proposed for describing the evolution of permanent axial deformation based on the results in the single-stage test and the multi-stage tests. It takes into account the number of cycles, the stress level, the water content and the fine content of the granular material. Two approaches are used: one based on the water contents and fine contents and the other based on suction values. The approach based on suction values needs less number of parameters to describe permanent axial deformation compared with the approach based on the water contents and fine contents while the two approaches present more or less the same accuracy. The simulation results show a very good capacity of the proposed approaches. These findings reduce the number of tests required to predict permanent axial deformation.
Granular materials are often used in pavement structures. The influence of anisotropy on the mechanical behaviour of granular materials is very important. The coupled effects of water content and fine content usually lead to more complex anisotropic behaviour. With a repeated load triaxial test (RLTT), it is possible to measure the anisotropic deformation behaviour of granular materials. This article initially presents an experimental study of the resilient repeated load response of a compacted clayey natural sand with three fine contents and different water contents. Based on anisotropic behaviour, the non-linear resilient model (Boyce model) is improved by the radial anisotropy coefficient γ3 instead of the axial anisotropy coefficient γ1. The results from both approaches (γ1 and γ3) are compared with the measured volumetric and deviatoric responses. These results confirm the capacity of the improved model to capture the general trend of the experiments. Finally, finite element calculations are performed with CAST3M in order to validate the improvement of the modified Boyce model (from γ1 to γ3). The modelling results indicate that the modified Boyce model with γ3 is more widely available in different water contents and different fine contents for this granular material. Besides, based on the results, the coupled effects of water content and fine content on the deflection of the structures can also be observed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.