Application of Electrical Resistivity Method in Building Foundation Study around Ansarudeen Primary School Adehun Area of Ado-Ekiti, Southwestern Nigeria.

The study evaluated the structural competency of the subsurface geological materials around Ansarudeen Primaryschool in Bolorunduro community, Adehun area of Ado Ekiti, Ekiti State, Nigeria to delineate the area that is suitable for buildingdevelopment. The ABEM SAS 1000 was employed for transmitting current and recording the resistivity value of the subsurfacelayers across the two traverses using the dipole-dipole and the Schlumberger arrays for horizontal profiling and vertical electricalsounding of the survey area respectively. Five VES points were occupied along traverses 1 and 2 with AB/2 of 150m. The fieldresistivity data were processed using Win RESIST and the Dipro software to generate the geoelectric sections of the survey area.The sounding curves generated were HK, KHA, and A, with HK having the highest number of occurrences. The interpreted resultshowed that the geoelectric section consist of five layers which are the topsoil, weathered layer, fractured basement layer, partlyfractured layer and the fresh basement rock. The resistivity value and subsurface layer thickness for the top soil varied from 115.3- 752.7 Ωm and 0.3 - 2.1 m respectively. The general overburden thicknesses were estimated at 11m and 23m respectively fortraverse 1 and 2. The pseudo section of the horizontal profiling and the geoelectric section of the Vertical electrical soundingrevealed similar subsurface lithology along traverse 1 and 2. The result however suggested foundation placement on traverse1along VES 3 and VES 2 of the geoelectric section or point 16-19 of the horizontal profiling pseudo section.