Goeelectric investigation of bedrock structures in the mini-campus of the Federal University of Technology, Akure, Southwestern Nigeria and the geotechnical significance

Abstract

Thirty-two Schlumberger and 26 Wenner vertical electrical soundings (VES) were conducted to delineate the structural/geotechnical features of the overburden/bedrock underlying the mini-campus of the Federal University of Technology, Akure, southwestern Nigeria. The results show that the resistivity values vary from 21-965Ώm and 300-10,500Ώm within the overburden and the bedrock respectively. Five significant depressions and two major normal fault axes were also delineated. Suspected fault zones or axes, bedrock depressions and low resistivity (<600Ώm) areas within the bedrock and average resistivity less than 300Ώm within the overburden, are considered geotechnically incompetent. The soil/rock in these zones may require reinforcement in order to enhance its bearing capacity and increase the life span of engineering foundations in the area. However, relevant intrusive geotechnical investigations are recommended in conjunction with the geoelectric survey in order to determine the most suitable foundation design in the study area.

Keywords: geosoundings, bearing capacity, competence, bedrock structures

Nigeria Journal of Pure and Applied Physics Vol. 4(1) 2005: 32-40