Volume 2, Issue 3, January - June, 2025

Mineralogical characteristics and engineering properties of genetically different residual soils in the northern part of Ondo State, Southwestern, Nigeria

Ikubuwaje Chrisopher Olatunde^1♦, Oyelami Charles Adebayo², Fakolade Omotoso Richard¹

¹Department of Minerals and Petroleum Resources Engineering Tech. Fed. Poly. Ado-Ekiti, Nigeria
²Department of Geology Federal University Oye-Ekiti, Oye-Are Road, Oye-Ekiti, Ekiti State, Nigeria

^♦Corresponding Author
Department of Minerals and Petroleum Resources Engineering Tech. Fed. Poly. Ado-Ekiti, Nigeria

ABSTRACT

The influence of mineralogical compositions on geotechnical properties of two genetically different soils around the northern part of Ondo State, Nigeria, was evaluated to better understand the complex engineering performance of clayey soils as derived by the parent rock. The soil samples collected from the region were subjected to XRD analysis, index strength tests, and statistical analysis. Geological mapping revealed Charnockite (Ch) and medium- to coarse-grained granite (OGe) rock types in the area. The OGe-derived soils have a dominance of low-activity clay mineral 1:1. On the other hand, the Ch-derived soils have a dominance of highactivity clay minerals of 2:1. The statistical analysis showed that there is no significant soil variation based on the size of its particle; however, it indicates that there is a significant difference in the coefficient of variations of their respective moisture content. Furthermore, Ch and OGe CBR values indicate a significant difference of 86 coefficients of variation, which account for a 75.61% reduction in the strength values between the two soil types. Ch-derived soil samples plot within the CH region of the plasticity chart, while OGe-derived soil samples plot within the CI region. Chderived and OGe-derived soils have optimum moisture content (OMC) mean values that fall above and within FMWH, (1997) recommended specifications, respectively. Ch-derived soils have a lower bearing capacity compared to OGe-derived soils. The OGe-derived soils have different and preferred engineering properties compared to the Ch-derived soils due to mineralogical differences. Hence, mineralogical characteristics of the parent material are responsible for behavioral differences in the engineering properties of soils derived from genetically different parent rock.

Keywords: Clay minerals, Geotechnical properties, Engineering soils, Statistical analysis.

Discovery Nature, 2025, 2(3), e4dn1049

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DOI: https://doi.org/10.54905/disssi.v2i3.e4dn1049

Published: 09 February 2025