UTILISING 2-D RESISTIVITY IMAGING TOMOGRAPHY IN INVESTIGATING STRUCTURAL FAILURE IN SOME BUILDINGS IN ADANKOLO CAMPUS OF FEDERAL UNIVERSITY LOKOJA, NIGERIAN NORTH CENTRAL AREA

One of the most used geophysical tools for characterization of the near surface is electrical resistivity tomography (ERT). The 2D resistivity survey was conducted along ten (10) buildings in Federal University Lokoja (Fulokoja), Adonkolo Campus. Dipole-dipole electrode configuration was conducted for data collection. Enhancing of measured field and calculated apparent resistivity details/data and interpretation of Electrical Resistivity Tomography (ERT) were generated using RES2DINV software which reveal a change in soil resistivity and type. From the result it is observed that the soil is made up of weathered migmatite rock which exist in layers of low resistivity, intermediate resistivity and high resistivity zone. The low resistivity zone is the uncompacted soil which provide an unstable foundation for the building while intermediate and high resistivity zone representing the fairly compacted to compacted soil which provide stable foundations for the buildings. The presence of clayey materials and oversaturated soil around the central part of the campus is the cause of the uneven ground settlement underneath these buildings causing the apparent cracks on some superstructures. The foundation of structures and buildings should be strengthened by mixing of the soil with gravels to enhance stability. Proper electrical resistivity survey and soil penetration test on the soil should be carried out prior to construction of buildings in the campus.