Drained Triaxial Response of Natural Clay Reinforced with Natural Hemp Fibers
Publication: International Journal of Geomechanics
Volume 24, Issue 7
Abstract
Reinforcement of soils with fibers generally increases the mechanical properties of the fiber-reinforced soil (FRS) system. However, published literature is limited to investigating the undrained response of clay and synthetic fibers, with few studies targeting natural clay and natural fibers under drained conditions. There is a need to study the response of fiber-reinforced clay systems under drained conditions to assess long-term stability. This paper investigated the drained shear strength and durability of clays reinforced with natural hemp fibers using isotropically consolidated drained triaxial tests, in which the fiber content, confining pressure, and compaction water content were varied. Results showed that the incorporation of hemp fibers improved the deviatoric stress at failure by up to 60%, which increased the drained cohesion and friction angle of the FRS by 7–10 kPa and 3–7°, respectively. The increase in cohesive intercept was not affected by the compaction water content, while the increase in friction angle was pronounced in specimens compacted at optimum water content (w = 18%). Durability tests showed that the improvement in strength due to hemp fibers diminishes after 3 weeks of curing prior to drained testing, indicating the dramatic negative impact of degradation of natural fibers on the mechanical performance of fiber-reinforced clay and the need for industrial treatment of the fiber.
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Data Availability Statement
All data, models, and codes generated or used during the study appear in the published article.
Acknowledgments
The authors express their gratitude to the Lebanese National Council for Scientific Research and the University Research Board (URB) at the American University of Beirut (AUB) for providing financial support for this research initiative.
Notation
The following symbols are used in this paper:
- Control
- specimens without any fiber reinforcement;
- c′
- cohesion intercept in consolidated drained tests (kPa);
- D
- diameter of the soil specimen;
- L
- length of the soil specimen;
- Lf
- length of the fiber;
- PI
- plasticity index (%);
- S
- degree of saturation (%);
- w
- water content (%);
- Xf
- gravimetric fiber content defined as the ratio of the weight of fibers to the dry weight of soil (%);
- γd
- dry unit weight of the soil (kN/m3);
- ϕ′
- friction angle for consolidated drained tests (°);
- σd
- deviatoric stress (kPa); and
- σn
- applied normal stress (kPa).
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Published In
International Journal of Geomechanics
Volume 24 • Issue 7 • July 2024
Copyright
© 2024 American Society of Civil Engineers.
History
Received: May 7, 2023
Accepted: Jan 13, 2024
Published online: Apr 23, 2024
Published in print: Jul 1, 2024
Discussion open until: Sep 23, 2024
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