Investigation of mechanical properties and micromechanisms of saline soil modified with synthetic fibers

Zhixin Liu ¹, Dongmei Chen ², Jili Qu ²

⁰University of Shanghai for Science and Technology, School of Environment and Architecture, Shanghai, China.

Plos One +

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August 14, 2025

View abstract on PubMed

Summary

Adding polypropylene, polyester, and glass fibers improves salt-affected soil's mechanical properties. Fibers enhance soil strength and reduce dissolution, with optimal results using polyester and glass fibers.

Area Of Science

Geotechnical Engineering
Soil Science
Materials Science

Background

Salt-affected soils pose significant challenges in construction and agriculture.
Improving the mechanical properties of these soils is crucial for infrastructure development.
Fiber reinforcement offers a promising approach to soil stabilization.

Purpose Of The Study

To investigate the effects of different fiber types and contents on the mechanical properties and microscopic morphology of sulfate-affected soil.
To analyze the unconfined compressive strength, shear strength, and dissolution characteristics of reinforced soil.
To understand the micro-mechanisms of fiber-soil interaction using Scanning Electron Microscopy (SEM) and Nuclear Magnetic Resonance (NMR).

Main Methods

Soil samples were reinforced with polypropylene, polyester, and glass fibers at various contents.
Unconfined compressive strength and shear strength tests were conducted.
Scanning Electron Microscopy (SEM) and Nuclear Magnetic Resonance (NMR) microanalysis were employed for microscopic examination.
Dry-wet cycling and dissolution tests were performed on the optimized sample.

Main Results

Polypropylene, polyester, and glass fibers increased the maximum dry density of salt-affected soil.
The highest unconfined compressive strength was achieved with 1% polyester fiber and 8% silica fume (1.98 times original).
Polyester fiber (1%) and glass fibers (5-7%) significantly enhanced unconfined compressive strength (1.43-1.57 times original).
Fiber addition reduced the dissolution coefficient, particularly with glass fibers.
SEM and NMR revealed that fibers create a clamping effect, bond with soil particles, and reduce porosity.

Conclusions

Fiber reinforcement effectively improves the mechanical properties of salt-affected soils.
Polyester and glass fibers show significant potential for enhancing soil strength and stability.
Fiber-soil interaction, characterized by clamping and bonding, is the primary mechanism for improvement.
Fiber-reinforced soil exhibits reduced susceptibility to dissolution, making it suitable for challenging environments.

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