Engineering geophysical study of the convocation square, Kaduna State University

Abstract

Geophysical investigation for engineering studies was carried out at the convocation square of Kaduna State University (KASU) main campus, Kaduna state, which falls within the Basement Complex of North-Western Nigeria. The study is aimed at assisting in the planning and development process of civil engineering works in the university. Vertical Electrical Sounding (VES) using Schlumberger array was carried out at ten (10) VES points. ABEM Terrameter (SAS 300 C) was used for data acquisition. Three major lithologic units were delineated from the electrical resistivity survey results comprising of topsoil, characterized by sandy/lateric materials, weathered basement and the fresh bedrock. Resistivity values for the various units range from 88 to 900 ohm-m, 111 to 247 ohm-m and 1300 to 32,000 ohm-m respectively. Depth to bedrock varies between 12 m to 42 m. Iso-resistivity maps of weathered basement, overburden and bedrock with respect to subsurface competency constructed from the VES data revealed that the study area is competent to permit constructions of engineering works. The degree of soil corrosivity varies from slightly-corrosive (80 ohm-m to 150 ohm-m) to practically non-corrosive (resistivity values >200 ohm-m). The results of this study show that corrosion prevention system should be put in place during the engineering design stages.

Keywords: Basement Complex, Soil Corrosivity, Engineering design