The Effect of Oil Pollution on the Engineering Properties of Construction Soils in Some Selected Oil Region of Nigeria: A Case Study of Four Oil Towns in Rivers and Delta States

Abstract

The nature of subgrade as well as basic information of soils for construction purposes is important for engineers, especially civil engineers and the general public. The primary aim of this research work is therefore to access the effect of oil spillage on the engineering properties of soils around the oil producing states of Nigeria. Four communities in two state of the Niger- Delta region of Nigeria were selected for investigation. These communities include Alesa (as sample A) and Aleto (as sample B) in Rivers state and Elume (as sample C) and Mereje (as sample D) in Delta state of the Niger- Delta region of Nigeria. Soil samples from these communities were collected at the subgrade depth of the oil spilled soils and was later subjected to laboratory examination. Important soil properties that were evaluated through laboratory investigation include soil shear strength test using triaxial test where the shear strength parameters were determined to enable evaluation of soil bearing capacity using Terzaghi’s equations. Others include soil strength (CBR) test, soil permeability test, and soil classification test as well as soil compressibility tests or one dimensional consolidation test. The results show that the oil pollution/ spillage have affected the engineering properties of construction soils in the four towns investigated to some degrees. The California Bearing Ratio (CBR) value of the subgrade, the Coefficient of Volume Compressibility,Mv, the Safe Bearing Capacity and the Coefficient of Permeability, K of the investigated soil , all fall below the accepted standard limit for soils to be used for construction purposes. This result will hopefully add to the existing knowledge as well as equipping the government and other relevant agencies for policy and regulatory development for the oil and gas, and construction industries for the sustenance of economic development in Nigeria. Therefore, before any meaningful civil engineering construction works can be done in these communities, the soils within the area will have to be subjected to series of engineering soil tests so as to equip the government and other interesting stakeholders with the requisite knowledge on how to apply appropriate soil remediation and soil stabilization techniques.