2018_EJRNL_PP_OLAWALE_OLAKUNLE_OSINOWO_1.pdf
Terbatas  
» Gedung UPT Perpustakaan
Terbatas  
» Gedung UPT Perpustakaan
Three Dimensional (3D) Electrical Resistivity Imaging (ERI) was carried out for pre-construction foundation
investigation of a proposed engineering construction site within the University of Ibadan Campus, south-western
Nigeria, where some distressed structures (offices and hostels) have been reported to show stress induced cracks
attributed to incompetent foundation support from rocks upon which they were constructed.
The 3D grid of resistivity data generated along parallel and equally spaced profiles stations presented the
resistivity distribution of the subsurface as well as delineated zones of relatively high resistivity values
(450–4500 ? m) in the east and lower resistivity zones (15–300 ? m) in the west. The study also delineates zones
of isolated low resistivity values (10–50 ? m) at the mid and west end of the field. The generated resistivity
distribution sections, maps and 3D model indicate spatial variation in resistivity value which varies both laterally
and vertically. The variation which is attributed to differences imposed by underlying rock’s structural and
geological rock composition resulted from complex rock coexistence as schist (quartz- and amphibolitic-schist)
and quartzite coexist as underlying rocks of the proposed construction site, especially since these rocks respond
to weathering differently.
The generated subsurface resistivity model guided selection of geotechnical investigation points which captures
spatial variation in subsurface physical properties as recorded by the measured subsurface resistivity.
Better guided geotechnical investigation provided needed information required to design appropriate foundation
support for the proposed engineering structure.