Geotechnical Assessment of Pavement Failure along Lagos-Ibadan Expressway

Abstract

Pavement failure has contributed immensely to loss of lives, disruption to normal daily activities and increase amount of money being spent on maintenance annually. One of the causes is associated with inadequate investigations on subgrade materials. This study aimed at examining the geotechnical parameters as factors of pavement failure along Lagos–Ibadan Expressway. Samples were collected at the failed and stable portions on some selected road segments and subjected to laboratory tests including Natural Moisture Content (NMC), Linear Shrinkage(LS), particle size distribution and California Bearing Ratio(CBR). The NMC along the failed sections was on the high side (ranged from 13.11% to 26.89%) compared with the stable sections (ranged from 11.11% to 16.40%). Most of the tested soils have percentage passing 0.075mm sieve more than 35% maximum required by the Federal Ministry of Works and Housing for subgrade materials. The maximum dry density(MDD) for the samples at failed and stable sections ranged from 1550 kg/m3 to 1860 kg/m3; 1650 kg/m3 to 1980 kg/m3 respectively while the Optimum Moisture Content(OMC) ranged from 8.30% to 20.30%. The soaked CBR values ranged from 2% to 17% while the unsoaked values ranged from 4% to 25%. The increase in NMC along the failed portions could be as a result of high water table along these sections. Some of the materials at failed locations had values of LS > 8% which suggests high susceptibility to shrinkage and swelling which results in differential settlement and contributed to pavement failure along these sections of the road. Keywords: Geotechnical, Pavement failures, subsurface investigations, Expressway, subgrade materials.

Implications of the Engineering Geological Properties of Soils in the Implementation of the Greater Jos Master Plan, North Central Nigeria

“…Also, the basalt derived soils showed higher moisture content against the granite derived soils. Reference [42] opined that generally MDD decrease while OMC increases with increase in fines, but this does not agree with results of the study area. Only samples 28 and 29 showed an increase in OMC with increase in percentage fines.…”

Integration of VLF-EM and VES data for pavement failure investigation in a typical basement complex terrain of southwestern Nigeria

“…The crystalline basement terrain of southwestern Nigeria presents challenges in geotechnical investigations due to the heterogeneous nature of the subsurface and the existence of localized geologic features [13,20]. In this study, the subsurface geology indicates substantially clayey subsoil with relatively low resistivity values and presence of geological features including fractures, faults and lateral inhomogeneity.…”

“…The degree of weathering and fracturing permits groundwater accumulation and the effect of rising water table. The bearing capacity of the layer is corresponding low [3,16,20].…”

“…Adverse effects of groundwater can be expected across the third layer as the features often store groundwater in the basement complex terrain [16,20]. This geoelectric layer constitutes a layer of low bearing capacity.…”

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

“…Prominent research works emphasized the need for thorough knowledge of the characteristics and behaviour of subgrade layer on which structures are built through geological, geotechnical and geophysical investigations (Okigbo, 2012;Ugwu and Ezema, 2013;Adelekan et al, 2017). Inadequate investigations of subgrade and other pavement materials prior to the commencement of road projects constitute pitfalls in road construction (Andrews et al, 2013;Aizebeokhai and Oyeyemi, 2014;Odunfa et al, 2018). Adequate knowledge of the geotechnical characteristics of underlying soils at construction sites has become a pre-requisite for foundation design and construction of civil engineering structures to mitigate failure of structures (Adigun et al, 2014;Awang et al, 2016).…”