Journal of Emerging Trends in Engineering and Applied Sciences: Research Areas

Article Title: Geoelectric and Electromagnetic Methods for Post Foundation Studies in a Typical Basement Terrain
by Ogungbemi Oluwaseun, S., Badmus Ganiyu, O., Ologe Oluwatoyin, Idowu Kayode A.

Abstract:
A combined geophysical investigation involving very low frequency electromagnetic (VLF-EM) and electrical resistivity methods were conducted at Ijapo Housing Estate, Akure, southwestern Nigeria, to assess its foundation integrity for future engineering construction in a bid to stamp out the persisting incidence of collapse building. VLF-EM profiling was undertaken along 19 traverses, with traverse lengths ranging between 180 and 1,200 m and station interval of 20 m. Thirty vertical electrical sounding (VES) stations were occupied within the study area. VLF-EM and VES data were quantitatively interpreted. VLF-EM mapped conductive and non-conductive zones and the result revealed concealed geological structures suspected to be fractures/faults. Geoelectric method delineated about four major geoelectric layers namely: the top soil, lateritic layer, weathered basement and the fresh basement and series of bedrock ridges and depressions. Failure of engineering structure(s) in a typical basement complex may result from sharp variation in lithological characteristic such as resistivity contrast, moisture content and the presence of linear geological features (faults and/or fractures) within the subsurface. This is exemplified within the study area characterized by competent and incompetent zones. Therefore, subsequent construction should be restricted to the competent zone, while building foundations within the incompetent zone should be anchored on the bedrock without exceeding the load bearing capacity.

Keywords: foundation, electromagnetic, geoelectric, bedrock, competent, conductive, ridges

Download full paper