Integration of Geophysical (Vertical Electrical Sounding) and Geotechnical Data for Subsurface Characterization of Materials Within the University of Ibadan, Southwestern Nigeria

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@article{1722686,
      author = {Oluwafemi Adebisi Adesope},
      title = {Integration of Geophysical (Vertical Electrical Sounding) and Geotechnical Data for Subsurface Characterization of Materials Within the University of Ibadan, Southwestern Nigeria},
      journal = {Iconic Research And Engineering Journals},
      year = {2026},
      volume = {10},
      number = {2},
      pages = {3677-3687},
      issn = {2456-8880},
      url = {https://www.irejournals.com/formatedpaper/1722686.pdf},
      abstract = {In terrains where weathering and lithological variability can significantly affect engineering conditions, precise subsurface characterization becomes essential for foundation design. In this study, Vertical Electrical Sounding (VES) and laboratory geotechnical investigations have been used to characterize various locations within the University of Ibadan, southwestern Nigeria. Six VES stations were surveyed using the Schlumberger array method while representative soil samples were tested for moisture content, particle size distribution, atterberg limits, specific gravity, compaction tests, CBR value, direct shear test and unconfined compressive strength (UCS). Four geoelectric layers of topsoil, lateritic/clayey material, weathered basement and fresh basement were interpreted through the use of VES. The resistivities of these materials were; 71-98 Ωm, 172-250 Ωm, 435-640 Ωm and 1,265-1,765 Ωm for topsoil, lateritic/clayey material, weathered basement and fresh basement respectively. Thicknesses of weathered basement were 8.5-10.4 m and fresh basement occurred at about 14.6-16.2 m. The soils are predominantly sandy, with about 95.5% passing 4.75 mm sieve and 2.88% passing 0.075 mm sieve. Moisture contents ranged from 12.88-17.13%, liquid limit was between 36-44%, plasticity index from 15-19% and specific gravity of 2.51-2.58. The Maximum Dry Density and Optimum Moisture Content ranged from 2.00-2.03 g/cm³ and 7.84-8.46% while the California Bearing Ratio (CBR), cohesion, friction angle and UCS values ranged from 5.41-7.72%, 4.53-5.93 kPa, 29.54-30.14° and 39.70-41.74 kPa, respectively. The results indicate a laterally variable weathering profile and relatively weak near-surface engineering characteristics. Integrated VES and geotechnical investigation provides a more reliable basis for foundation assessment than either method alone.},
      keywords = {Vertical Electrical Sounding; Subsurface Characterization; Maximum Dry Density; Friction Angle.},
      month = {August},
      doi = {https://doi.org/10.64388/IREV10I2-1722686}
  }