Subsoil Conditions of Parts of Niger Delta Wetland, Nigeria

The subsoil conditions of Gbaran North Bank area, parts of the Nigerian wetland were evaluated
using both disturbed and undisturbed soils, which were subjected to various laboratory tests adopting
the British Standards methods, with the aim of establishing the subsoil conditions of the area as it
affects use of the soils for various kinds of construction. The liquid limit recorded values between 37%
and 50%, plastic limit range of 11% – 23% and attendant plasticity indices of 20% - 33%. The soils
classified as highly plastic on the basis of their plasticity index and showed expansivity range of low –
medium, while the swelling type was critical – non-critical. The soils recorded shear strength values of
39 – 42 KN/m2 with coefficient of consolidation Cv values of 0.4 – 30.5 m2/yr. The soils from the
results showed tendencies towards expansion and therefore pose a problem to construction except
precautionary measures are taken to ensure safety and durability of structures. Improved waste and
flood management on the other hand, will facilitate sustained shear strength properties of the soils
thereby enhancing their constructional values.