Coastal Foundation Investigation Using Geoelectrical and Geotechnical Techniques at Okerenkoko, Delta State, Nigeria

Abstract

This report presents an Application of Geoelectrical and Geotechnical Investigation of Coastal Foundation at Nigeria Maritime University (NMU) Okerenkoko Campus, Warri South West, Delta State, to determine the subsurface Lithology, depths to bedrock and moist content of the soil. Vertical electrical sounding (VES) survey were conducted using a resistivity meter along, three (3) profiles, at 75 m and 4 stations at 25 m interval from each sounding point; and a total of 12 VES measurement were made. The results of the VES suggest that the entire subsurface of the area, is made up of three (3) distinctive Lithologies, the First layer is Topsoil with resistivity value between 22.38 and 6880 Ωm, the second layer is a Loose Sand with resistivity values variation between 5.393 to 896.5 Ωm and the third layer is consolidated Sandstone with resistivity value of 14.12 to 675.5Ωm. Geotechnical investigation was carried out to check the soil Moisture content therefore knowing the elevation where the high percentage of mixture is located and water filling the void space. The result of the geophysical investigation of this work shows that the third layer is generally consolidated sandstone and the Geotechnical investigation of this work shows that the Western part of the Site has high percentage of mixture and water while the Eastern part has low percentage of mixture content, it is therefore advisable for engineers to consider this in their design. The heavy foundation should be situated towards the Eastern section of the site, where the bedrocks are consolidated and less mixture content, to avoid any form of future building collapse.