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Influence of Strain Rate on the Shear Strength Properties of Lateritic Soils from Six Local Government Areas of Ibadan Metropolis, Southwestern Nigeria
Subject area: Science,Engineering and Technology · Area of research: Foundation and Geotechnical Engineering
DOI: 10.64388/IREV10I4-1723627
Abstract
Laboratory shear strength parameters of lateritic soils are routinely measured at a single, arbitrarily selected displacement rate, although field loading rates span several orders of magnitude. This study examined whether strain rate influences the Mohr–Coulomb shear strength of lateritic soils from six Local Government Areas (LGAs) of Ibadan metropolis, southwestern Nigeria: Akinyele, Egbeda, Ido, Lagelu, Oluyole and Ona-Ara. Disturbed samples were taken from one borrow pit per LGA at 1.0–1.5 m depth and characterised by natural moisture content, bulk and dry density, specific gravity, particle-size distribution and Atterberg limits. Consolidated direct shear tests (ASTM D3080) were then carried out at normal stresses of 50, 100 and 150 kPa and at two displacement rates, 0.5 and 1.0 mm/min. The soils are predominantly sandy (fines content 1.2–9.1%) with plasticity indices of 4.3–10.9%; the Ido soil is non-plastic. Fitted friction angles ranged from 19.5° to 38.7° (R² = 0.81–1.00), whereas cohesion intercepts were small and frequently negative, an artefact of fitting three-point envelopes that makes them indicative only. Doubling the displacement rate increased mean cohesion by 6.2 kPa and mean friction angle by 1.1°, but neither change was statistically significant across the six LGAs (paired t-test, p = 0.584 and 0.766) and the direction of change was inconsistent between LGAs. At LGA level, only Egbeda showed a significant increase in peak shear stress (mean +27.8 kPa, p = 0.0018). Over the 0.5–1.0 mm/min range, results obtained at either rate can be used interchangeably for preliminary design in five of the six LGAs, whereas Egbeda warrants site-specific multi-rate testing. Wider rate ranges, more normal stress levels and replicate specimens are needed to confirm and explain the localised response.
Keywords
lateritic soil; strain rate; direct shear test; Mohr–Coulomb criterion; rate sensitivity; Ibadan
How to cite this paper
@article{1723627,
author = {Oyebade Pelumi Samuel, Ayininuola G. M.},
title = {Influence of Strain Rate on the Shear Strength Properties of Lateritic Soils from Six Local Government Areas of Ibadan Metropolis, Southwestern Nigeria},
journal = {Iconic Research And Engineering Journals},
year = {2026},
volume = {10},
number = {4},
pages = {234-248},
issn = {2456-8880},
url = {https://www.irejournals.com/formatedpaper/1723627.pdf},
abstract = {Laboratory shear strength parameters of lateritic soils are routinely measured at a single, arbitrarily selected displacement rate, although field loading rates span several orders of magnitude. This study examined whether strain rate influences the Mohr–Coulomb shear strength of lateritic soils from six Local Government Areas (LGAs) of Ibadan metropolis, southwestern Nigeria: Akinyele, Egbeda, Ido, Lagelu, Oluyole and Ona-Ara. Disturbed samples were taken from one borrow pit per LGA at 1.0–1.5 m depth and characterised by natural moisture content, bulk and dry density, specific gravity, particle-size distribution and Atterberg limits. Consolidated direct shear tests (ASTM D3080) were then carried out at normal stresses of 50, 100 and 150 kPa and at two displacement rates, 0.5 and 1.0 mm/min. The soils are predominantly sandy (fines content 1.2–9.1%) with plasticity indices of 4.3–10.9%; the Ido soil is non-plastic. Fitted friction angles ranged from 19.5° to 38.7° (R² = 0.81–1.00), whereas cohesion intercepts were small and frequently negative, an artefact of fitting three-point envelopes that makes them indicative only. Doubling the displacement rate increased mean cohesion by 6.2 kPa and mean friction angle by 1.1°, but neither change was statistically significant across the six LGAs (paired t-test, p = 0.584 and 0.766) and the direction of change was inconsistent between LGAs. At LGA level, only Egbeda showed a significant increase in peak shear stress (mean +27.8 kPa, p = 0.0018). Over the 0.5–1.0 mm/min range, results obtained at either rate can be used interchangeably for preliminary design in five of the six LGAs, whereas Egbeda warrants site-specific multi-rate testing. Wider rate ranges, more normal stress levels and replicate specimens are needed to confirm and explain the localised response.},
keywords = {lateritic soil; strain rate; direct shear test; Mohr–Coulomb criterion; rate sensitivity; Ibadan},
month = {October},
doi = {https://doi.org/10.64388/IREV10I4-1723627}
}