The Geotechnical Investigation of Subsoil Materials in a Typical Basement Terrain, Southwestern Nigeria- A Case study.

Main Article Content

Philips Omowumi Falae
Ayo Ogundana


Geotechnical investigation of the subsurface materials of a proposed Primary Health Center (PHC) in Modeke Oyo East Local Government Area (OELGA). of Oyo State has been conducted. The investigation is aimed to determine the suitability of the site for the proposed Bungalow building by assessing the subsoil strata that underlie the area. Three (3) points were tested to depth of 4.75m using a 2.5-ton DCPT equipment, while three (3) trial pits were dug to a depth of 1.5m with the aid of hand auger, and various lab analysis were conducted
on selected samples from the trial pits. The result obtained from the DCPT indicates that subsurface is made up of stiff to very stiff sandy lateritic clay underlain by very stiff to hard sandy lateritic clay with hard pans layers. The allowable bearing pressure was observed to increase with depth to 4.75m further confirmed the subsurface lithologies. The Allowable Bearing Pressure (qa) in kN/m2) with a range of values 81 – 256 kN/m2, 54 – 155 kN/m2 and 162 – 338 kN/m2 for DCPT points 1, 2, and 3 respectively, indicate a Safe Bearing Pressure that
can support load up to 45 kN/m with factor of safety of 2.5. Sieve analysis results revealed that the soil is well graded with dominant gravel which show a well-drained soil with good strength characteristics. Liquid limits ranged from 26.7% to 43.3%, plastic limits from 15% to 27% and plasticity index from 9.7% to 27.3%, thus indicating low to medium compressibility. The natural moisture contents values range between 4% and 15%, indicating lateritic clay of low to medium plasticity with low moisture content. Based on the above deductions, it can be concluded that, the factor of safety of 2.5 calculated from the allowable bearing pressure from the CPT, low to medium compressibility from Atterberg limits test and moisture content below 15% show that the investigated site is good and could safely support a bungalow building as proposed.

Article Details

How to Cite
Falae, P. O., & Ogundana, A. (2022). The Geotechnical Investigation of Subsoil Materials in a Typical Basement Terrain, Southwestern Nigeria- A Case study. ABUAD International Journal of Natural and Applied Sciences, 2(2), 116-122.


Adeoti L, Ojo AO, Adegbola RB, Fasakin OO (2016) Geoelectric assessment as an aid to geotechnical investigation at a proposed residential development site in Ilubirin, Lagos, Southwestern Nigeria. Arab J Geosci 9: 338.
Ako B. D, Ajayi, T. R., Arubayi, J. B, Enu, E. I (2005) The groundwater and its occurrence in the coastal plains sands and alluvial deposits of parts of Lagos State, Nigeria Water Resources 16: 7-17.
Cosenza P, Marmet E, Rejiba F, Cui YJ, Tabbahgh A, et al. (2006) Correlations between geotechnical and electrical data: A case study at Garchy in France. J Appl Geophys 60: 165−178.
Falae P.O., (2014) Application of Electrical Resistivity in Buildings Foundation Investigation in Ibese Southwestern Nigeria. Asia Pacific Journal of Energy and Environment 1(2). 95-105.
Fajana A.O (2021) Geohazard characterization of subsurface materials using integrated geophysical methods for post foundation studies: a case study. Modeling Earth Systems and Environment (2021) 7:403–415
Kamal, M. A., Ibrahim, M. and Abdelazim, M. I. (2015). Geotechnical properties of Sabkha Soil in the southern part of AlKhobar city, KSA. Journal of Engineering Research and Applications, 5: 24-29.
Kirar, B., Maheshwari, B., Muley, P. (2016). Correlation between shear wave velocity (Vs) and SPT resistance (N) for Roorkee region. Int. J. Geosynthetics Ground Eng. 2:1, 1–11.
Meshida, E. A. and Ayolabi, E. A. (2011). Need for Geo-scientific Maps for a Reasonable Planning and Physical Development of Coastal and Wetland Areas of Nigeria. Proceedings of the Environmental Management Conference, Federal University of Agriculture, Abeokuta, Nigeria.
Oloruntola, M. O., Bayewu, O. O., Mosuro, G. O., Folorunso, A. F and Ibikunle, S. O (2017). Groundwater occurrence and aquifer vulnerability assessment of Magodo Area, Lagos, Southwestern Nigeria. Arab J. Geosci. 10, 110 – 123
Oyedele, K. F. and Olorode, D. O. (2011). On site Investigation of Subsurface Condition using Electrical Resistivity Method and Cone Penetration Test at Medina Brook Estate, Gbagada, Lagos, Nigeria. World Applied Science Journal, 11:9, 1097 – 1104.
Oyediran I.A., and Falae P.O (2018) Integrated Geophysical and Geotechnical Methods for Pre-Foundation Investigations. J Geol Geophys 8: 453. doi: 10.4172/2381-8719.1000453
Sánchez-Garrido, A.J.; Navarro, I.J.; Yepes, V. Evaluating the sustainability of soil improvement
techniques in foundation substructures. J. Clean. Prod. 351, 131463