Geotechnical Investigation of Subsurface Parameters Necessary for Construction of a Flyover in Woji, Port Harcourt, Nigeria

Abstract

Geotechnical properties of the soil have been carried out at the construction site of an overhead bridge in Port Harcourt, Rivers State, Nigeria. The project is a 230 m long overhead bridge crossing between first and second artillery in Port Harcourt, Nigeria. Two tests that were carried out on the soil are the Atterberg limit test and particle size analysis test. The results reveal that the liquid limit is 36, 8, the plastic limit is 21.1 and the plasticity index is 15.7. This implies that the Atterberg limits are slightly above the recommended standard set by the Federal Ministry for Works and Housing, however, considering the swampy wet nature of the environment within the Port Harcourt Metropolis, the results obtained still fall within a range that can be worked with few modifications. The average diameter of the particles (D value) are D10=0.05, D30=0.17, D60=1.12 Cu=1.5 and Cc=0.5. The soil sample tested shows proper gradation since the coefficient of uniformity (Cu)>>4.