This paper DOI: 10.5281/zenodo.4275598

Geoengineering Spatial Mapping for Safe and Economic Design of Building and Earthwork Structures in Northern Part of Ondo State, Nigeria

Olumuyiwa Olusola Falowo^1*, Williams Kola Olabisi¹

¹Department of Civil Engineering Technology, Rufus Giwa Polytechnic, Owo, Nigeria

 * Corresponding author Email: oluwanifemi.adeboye@yahoo.com

Abstract: The objectives of the study are to assess the engineering competence of the subsoil and develop a subsoil competence map for northern parts of Ondo State, Nigeria, using integrated remote sensing, geotechnical, geophysical and geological investigations, and hydrogeological measurements. The generated subsoil competence map was obtained by integrating the results data of these parameters measured: topsoil resistivity and thickness, plasticity index, shear strength, allowable bearing pressure, soil association, lineament density, and groundwater level. Based on the design, the obtained settlement values were within the 25 mm commonly recommended.  Consequently, the map classified the study area into moderate competence (60%), high competence (35%), and very high competence (5%). The corrosivity map of the topsoil shows predominant moderate to mildly corrosivity, prominently in Ose and Akoko areas and constitutes about 70 %. This type of corrosivity is suitable for buried communication equipment and electrodes. In conclusion, shallow foundations such as pad or raft foundation of reinforced concrete can be adopted for buildings. Also, the soil geotechnical properties will support adequately road structures and various earthworks. However, areas characterized by moderate competence material can be improved by less expensive mechanical compaction and proper use of admixtures (lime, cement, bituminous addition, sand/gravel grading) to increase bearing capacity, compaction, and shear strength, which will invariably reduce compressibility, settlement, and permeability.

Keywords: Soil competence, foundation, groundwater level, bearing capacity, remote sensing