Abstract

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The study location is within the coastal plain sand of Akwa Ibom State. The area lies within a subhorizontal geomorphologic terrain with a measure of undulations arising from uneven surface area erosion. The study revealed that the soils are loose, coarse texture with 78 – 80% sandy fractions having single grain structure from unconsolidated materials of recent alluvial deposits. The soils are strongly acid in reaction with pH values between 4.8 and 5.8 which could be attributed to leaching of the basic cations to lower depth. Organic carbon content ranged from moderately low 1.50% to high 2.38% due probably to high surface litter and vegetation cover. Since the ultimate bearing capacity depends upon the angle of internal fraction (ф) and hence the penetration number (N), it was related directly to the N at profiles 1, 2, 3 and 4 from the existing surface, cohesion value of 25 kN/m2 was applied and the allowable bearing pressure of 18.5 kN/m2, 17.1 k/Nm2, 54 k/Nm2, and 66 kN/m2 were obtained for profiles 1, 2, 3 and 4 respectively by applying a factor of safety of 3.0. The higher the elevation, the higher the plasticity and the swelling potential; and the lower the bearing capacity and strength of the building sub-grade.

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