GEOPHYSICAL INVESTIGATION FOR POST-FOUNDATION ASSESSMENT WITHIN EKITI STATE UNIVERSITY, ADO EKITI, SOUTHWESTERN NIGERIA

Abstract

This study has evaluated the post-construction subsoil integrity of a distressed building in Ado-Ekiti, Southwestern Nigeria, to decipher the in-situ lithology and structural disposition. Four traverses of 100 m length were established in approximately E-W direction with an inter-station spacing of 10 m. Two Geophysical methods were deployed including the ground magnetic method using Proton Precession Magnetometer and Electrical Resistivity method utilizing 2D Electrical Imaging and Vertical Electrical Sounding (VES) techniques. Twelve (20) VES station points were acquired within the investigated area using Schlumberger configuration which gave relevant information on layer stratification and geoelectric parameters. The obtained results from the VES showed four geo-electric layers comprises topsoil, clayey layer, weathered layer, fractured bedrock, and fresh basement. Low apparent resistivity was delineated from the 2D imaging exhibiting unfit materials at distance between 50 to 75 m and 80 to 100m. The magnetic results showed a series of bedrock ridges and depressions. The integration of results revealed that the majority of the study areas are unsuitable except for central parts which indicate appreciable competence and stability.

Keywords

• foundation failure
• differential settlement
• ves
• resistivity
• 2d electrical imaging