Probability functions of road failures in a typical basement complex region, South-western Nigeria: A case study of Akure - Oba Ile Airport Road

Abstract

In this study, effort has been made to achieve a comprehensive geophysical investigation on immediate and remote causes of structural/foundation failures, specifically highway(s) within the southwestern basement complex region of Nigeria. Geophysical survey involves the use of Very Low Frequency Electromagnetic method (VLF-EM) which was complemented with electrical resistivity method using two techniques; 2D Electrical Resistivity Tomography (ERT) and Vertical Electrical Sounding (VES) along Akure/Oba-Ile Airport Road, which covers a pilot test of 600 m. The VLF-EM survey produced EM anomalies and identified possible linear features along the study area. The results obtained from the VES were used to determine the second order parameters for determination of subsurface integrity/competence. The geoelectric sections identified three to five geoelectric/geologic subsurface layers along the traverse. The ERT gave information on the subsurface characteristics whose section delineated five major geologic layers comprising of the topsoil, weathered basement, fractured zone, partly fractured basement and the fresh basement. This shows that fracture and weathering are responsible for the structural failures along the study area which are products of probability functions of geodynamics. The methodology can be adopted as a model to proficiently and quickly detect changes in subsurface resistivity, integrity and identify anomalous zones which can serve as useful tool in the understanding of the probability functions of geodynamics that can bring structural and foundation failures within the basement complex region.

Electrical Resistivity and Geotechnical Attributes and The Dynamics of Foundation Vulnerability

“…The issues concerning foundation studies have remained a burning concern in the mind of geoscientists and civil engineers (Bawallah et al, 2020). Whereas, the spates of foundation vulnerability and subsequent failures that were reported in some parts of African and especially Nigeria has assumed a worrisome dimension, hence to evaluate the factors that are responsible for this foundation vulnerability in terms of depth of investigations, nature of materials, structural trends, geodynamic factors, the relevance of Electrical Resistivity and Geotechnical attributes and their significance in evaluation of foundation sustainability (Ilugbo et al, 2018;Bawallah et al, 2019a;Bawallah et al, 2019b;Bawallah et al, 2020;Oyedele et al, 2020).…”

Application of Electrical Resistivity Method to Site Characterisation for Construction Purposes at Institute of Agriculture Research and Training Moor Plantation Ibadan

“…The causes of foundation failure may be as a result of differential settlement within a weak subsurface layer or the presence of geologic fissures such as faults, fractures, and shear zones beneath the construction site (Oyedele et al, 2020). Despite this clear reason, site engineers sometimes fail to incorporate pre-construction investigation (Geophysical survey) in their job schedule due to cost, and the findings are not taken into consideration in the design, and construction phase (Ilugbo et al, 2018a, Adebiyi et al, 2018.…”