Use of electrical resistivity technique for engineering site investigation: a case study from Ado-Ekiti, South-Western Nigeria

Abstract

A geophysical investigation of part of the Federal Polytechnic Ado-Ekiti campus involved use of the electrical resistivity method for foundation studies. A combined geophysical technique of vertical electrical sounding and horizontal profiling was employed. The quantitative interpretation of the geophysical results allowed the layer parameters to be established, while the isoresistivity maps at varying electrode spacing provided information on the nature, type and competence of the underlying material. The qualitative interpretation of the horizontal profiling delineated the contact zone. Also analysis of transverse unit resistance showed the relevance of this parameter as an index in predicting engineering properties of the rock.
The presence of moderately thick (1.5 – 16.5m) clay has been established in this area; therefore the use of raft foundation and/or any other foundation that is commensurate with civil engineering standard is suggested for high rise structures.

Keywords: bedrock integrity, transverse unit resistance, foundation.

Global Journal of Pure and Applied Sciences Vol. 11(4) 2005: 543-552