Study on Application of the Electrical Resistivity in Building Foundation Study around Led School Area in Bishini, Northwestern Nigeria

Non availability of potable water and accommodation of staff and students constitute challenges in
most boarding schools warranting the need to develop housing structures around the school areas
that will conveniently accommodate enough people. Construction of buildings for students’
accommodation need cautious approach to avoid the incidence of building failures and collapses that
constitute major issues of concern, affecting urban development in Nigeria and the world at large. This
study evaluated the structural competence of the subsurface geological materials around Led School
Area in Bishini, NW Nigeria to delineate the area that is suitable for building development. Twenty
Seven vertical electrical soundings (VES) points were occupied in the study area employing ABEM
Terrameter SAS 300C with Schlumberger electrode configuration of maximum electrode separation
AB/2=150 m. The field resistivity data were interpreted using Win RESIST software. The results from
the 2-D interpretation of the VES data were used to prepare the geoelectric sections along four cross
sections. The interpreted results showed that the geoelectric sections consist of three to five layers,
which are: Top soil, Laterite, Lateritic clay, weathered layer and Fresh basement. The resistivity value
and subsurface layer thickness for the top soil varied from 191.7 Ω m to 8146 Ωm and 0.3 m to 7.0 m
respectively. The Laterite layer had resistivity values ranging from 1000 Ωm to 1627.3 Ωm and
thickness between 1.8 m and 2.5 m. The weathered layer resistivity varied from 33.5 Ω m to 850 Ω m
with thickness of 3.6 m to 44 m. The bedrock resistivity ranged from 1238.3 Ωm to 33438.6 Ωm.
Geoelectric sections along profile 4 and 1 revealed the thinnest sequence of loose overburden
materials and fresh basement at the shallowest depth. The area covered by these profiles is suitable
for building development. Building development should not be located along profiles 2 and 3 due to
relatively thick weathered layer. However the area may be considered for citing borehole to harness
its groundwater potentials.