2D Electrical Resistivity Surveys and Geotechnical Studies for Pavement Failure Evaluation, North- Central, Nigeria | Technical Journal 2022

Author(s)

M. O. Oloruntola Department of Geosciences, University of Lagos, Lagos, Nigeria

D. O. Obasaju Department of Earth Sciences, Kogi State University,Anyigba,Nigeria

S. Oladele Department of Geosciences, University of Lagos, Lagos, Nigeria

V. Ojekunle Department of Geosciences, University of Lagos, Lagos, Nigeria

C. Baiyegunhi Department of Geology, University of Limpopo

Abstract

A 2D resistivity survey was combined with geotechnical tests to gain an insight into the influence of the underlying subgrade soils on the failed Ajaokuta-Anyigba Highway. Resistivity data from twelve (12) 2D traverses using Dipole-Dipole Array were complemented with geotechnical tests on twentyone (21) subgrade soil samples from the unstable and stable sections of the highway. The geophysical results revealed that the unstable and stable sections are underlain by a continuous stretch of subgrade soils with low (< 100 Ohms.m) and high resistivities (100 1000 Ohms.m) interpreted as clayey and silty-sand respectively. Results of Geotechnical tests showed that the subgrade soils of the unstable segment have higher fines (52 - 64%), higher liquid limit (21.3 - 46. 0), higher plasticity index (12.7 - 38.8), a lower amount of sand (36 - 48 %) than subgrade soils of the stable section. Compaction test revealed that subgrade soils of the unstable sections have poorer compaction characteristics: Optimum Moisture Content, OMC (9.62 - 18.7%), and maximum dry density, MDD (1.7 - 2.03 g/cm3) than the subgrades of the stable section. Unsoaked and soaked California Bearing ratio (CBR) were not only lower than those of the stable section but fell below relevant acceptable standards. The study showed that the low resistivity and poor geotechnical properties of the subgrades are major geological contributors to the instability of the pavement.

Publication Details

Page(s) 1-7

DOI DOI not available

Published Journal: Technical Journal, Volume: 27, Issue: 1, Year: 2022

Keywords

resistivity Clay Highway failure Subgrade Geotechnical properties

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