Effective skeleton stress and void ratio for constitutive modelling of fiber-reinforced sand

Gao, Z. , Lu, D. and Huang, M. (2020) Effective skeleton stress and void ratio for constitutive modelling of fiber-reinforced sand. Acta Geotechnica, 15, pp. 2797-2811. (doi: 10.1007/s11440-020-00986-w)

Abstract

Inclusion of flexible fibers such as polypropylene and polyester is an effective method for soil improvement, as it significantly enhances the soil strength and ductility. A proper constitutive model is essential for assessing the stability and serviceability of fiber-reinforced slopes/foundations. A new method for constitutive modeling of fiber-reinforced sand (FRS) is proposed. It assumes that the strain of FRS is dependent on the deformation of the sand skeleton only, while the effective skeleton stress and effective skeleton void ratio, which should be used in describing the dilatancy, plastic hardening and elastic stiffness of FRS, are affected by fiber inclusion. The effective skeleton stress is dependent on the shear strain level, and the effective skeleton void ratio is affected by the fiber content and sample preparation method. A critical state FRS model in the triaxial stress space is proposed using the concept of effective skeleton stress and void ratio. Four parameters are introduced to characterize the effect of fiber inclusion on the mechanical behavior of sand, all of which can be easily determined based on triaxial test data on FRS, without measuring the stress–strain relationship of individual fibers. The model is validated by triaxial compression test results on four fiber-reinforced sands under loading conditions with various confining pressures, densities and stress paths. Potential improvement in the model for incorporating fiber orientation anisotropy is discussed.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Huang, Mian and Gao, Dr Zhiwei
• Authors: Gao, Z., Lu, D., and Huang, M.
• College/School: College of Science and Engineering > School of Engineering > Infrastructure and Environment
• Journal Name: Acta Geotechnica
• Publisher: Springer
• ISSN: 1861-1125
• ISSN (Online): 1861-1133
• Published Online: 19 May 2020
• Copyright Holders: Copyright © 2020 The Authors
• First Published: First published in Acta Geotechnica 15:2797-2811
• Publisher Policy: Reproduced under a Creative Commons licence