Effects of fibre additions on the tensile strength and crack behaviour of unsaturated clay

Wang, Jianye; Hughes, Paul N.; Augarde, Charles E.

Abstract

Desiccation cracking in clay soils is a combined mechanical and hydraulic problem and such soils can be improved by various methods including reinforcement with fibres. The relationships between tensile strength, cracking resistance and water-retention properties of fibre-reinforced fine-grained soils lack coverage in the literature to date. In this study, these three properties are evaluated and connected by way of a series of tensile strength and desiccation cracking tests on fibre-reinforced London clay. The results confirm that increased fibre addition delays the occurrence of peak stress and changes failure behaviour from brittle to ductile. The tensile strength increment gets higher as water content decreases, and reaches a maximum value of 460 kPa when the water content is 12%. The crack intensity factor reduces from 7.20% to 0.89% when 12 mm long fibre is used at a ratio of 0.9%. Fibre reinforcement also changes the crack development pattern by reducing the size of large cracks and increasing the proportion of small individual cracks. However, the presence of fibres was not observed to change the water-retention properties of the soil, indicating that the tensile improvement comes from the pull-out resistance of the fibres rather than suction changes.

Citation

Wang, J., Hughes, P. N., & Augarde, C. E. (2023). Effects of fibre additions on the tensile strength and crack behaviour of unsaturated clay. Ground Improvement, 176(2), 108-120. https://doi.org/10.1680/jgrim.21.00006

• Journal Article Type: Article
• Online Publication Date: Jan 27, 2022
• Publication Date: 2023-05
• Deposit Date: Oct 30, 2022
• Publicly Available Date: Jan 27, 2023
• Journal: Proceedings of the Institution of Civil Engineers - Ground Improvement
• Print ISSN: 1755-0750
• Electronic ISSN: 1755-0769
• Publisher: ICE Publishing
• Peer Reviewed: Peer Reviewed
• Volume: 176
• Issue: 2
• Pages: 108-120
• DOI: https://doi.org/10.1680/jgrim.21.00006
• Public URL: https://durham-repository.worktribe.com/output/1190068