Deformation Characteristics of Coastal Plain
Sands at a Water Treatment Plant Site,
Calabar, South-Eastern Nigeria


E. O. Esu,

Department of Geology, University of Calabar, Nigeria


A. O. Ilori

Civil Engineering Department, Federal Airports Authority of Nigeria, Calabar Airport, Nigeria


The 25.4 mm permissible settlement value for sandy soils was in dispute at a water treatment site works in Calabar, South-eastern Nigeria. The terrain is underlain by Tertiary-Recent sediments of the Benin Formation of the Niger Delta. Preliminary soil tests had shown a predominantly sandy soil with up to 40% fines (materials passing sieve no 200). Consolidation tests carried out on undisturbed soil samples obtained from the site for the water filter unit shows a preloaded soil with consolidation indices (mv, Cc, K) having values comparable to reported values for some clays; for example the Upper London Blue clay and the Cincinnati clay. The implication of this to the assumed permissible value of 25.4mm for the proposed structure is the subject of this article.

Keywords: Consolidation, sands, fines, Compresibility, Permeability, Settlement, Calabar, Nigeria.

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