Geophysical and Geotechnical Assessment of Sub-Grade Condition along Proposed Roads at Lagos State University of Science and Technology, Ikorodu, South-West Nigeria.

Abstract:

In most parts of the world, road failure has contributed to major problems leading to the death of so many people, causing traffic hazards, accidents and also increasing the rate of damage to vehicles. This research is to assess the geophysical and geotechnical conditions of proposed roads to be constructed in the Lagos State University of Science and Technology, Ikorodu, South-West, Nigeria. To achieve this, Electrical resistivity tomography (ERT) at 5 m spacing and Dynamic Cone Penetration Test (DCPT) at intervals of 50 m were deployed on five (5) profiles of 250 m each. The results show that the California Bearing Ratio (CBR) values calculated from DCPT range from 1.67% to 98.71% revealing very poor to excellent base/sub-grade material while the electrical resistivity tomography shows that the resistivity values ranges from 113.5 to 1266 Ωm revealing subsurface signatures of incompetent sandy clay, fairly competent sandy clay, fairly competent clayey sand and competent sand/dry sand materials. The areas of incompetence can be evacuated and compacted to facilitate better and more durable road constructions in the study area.