Open AccessGEOTECHNICAL INVESTIGATION OF THE PROPOSED IFE DAM SITE AT KAJOLA VILLAGE, ILE-IFE, SOUTHWESTERN NIGERIA
Author(s) -
O. O. Ajayi,
K. A. Adekoya,
O. P. Egwuatu,
C. I. Konwea
Publication year - 2021
Publication title -
geological behavior
Language(s) - English
Resource type - Journals
eISSN - 2521-0890
pISSN - 2521-0491
DOI - 10.26480/gbr.02.2021.28.33
Subject(s) - overburden , geology , lithology , vertical electrical sounding , geotechnical engineering , shearing (physics) , topsoil , electrical resistivity and conductivity , basement , mining engineering , geomorphology , groundwater , petrology , soil water , aquifer , soil science , archaeology , history , electrical engineering , engineering
Geological and geophysical investigations were conducted to assess the competence and structural integrity of the foundation site of the proposed Ife-dam at Kajola Village, Ile-Ife, Southwestern Nigeria. Geological investigation along the two (2) proposed dam axes revealed that the overburden material is loose to dense with angular shearing resistance (ɸ) of 27o to 41o. The soils are predominantly elastic silts; cohesive with considerable strength and stability. Geophysical investigation involving the Schlumberger Vertical Electrical Sounding delineated four (4) lithologies namely: topsoil with resistivity of 69 – 558 Ωm and thickness between 1.5 and 4.0 m; weathered sandy layer with resistivity from 123 – 586 Ωm and thickness between 6.5 and 20.4 m; partially weathered/ fractured basement with resistivity from 60 – 220 Ωm and thickness between 6.5 and 14.0 m; and the fresh basement rock with resistivity from 1337 – 10683 Ωm. There are indications of fractures at a depth of 32 m beneath Axis B extending to Axis A at a depth of 35 m. The subsurface materials are suitable to host a dam. Axis B is more appropriate for the dam axis, although the fracture zone should be factored into the design of the dam to prevent water seepage.