Geotechnical Properties of Foundation Soils in Jos-Bukuru Metropolis, Naraguta (Plateau State), in Relation to Observed Cracks on Buildings in the Area

Abstract

Collapse of engineering structures such as buildings erected on clayey or expansive soils occur regularly in the study area. Thus, the aim of this study is to evaluate the geotechnical properties of soils of Bukuru Metropolis in relation to building collapse. Eight (8) representative soil samples were collected from various locations in the study area within the Eastern part of Naraguta sheet, 168. Moisture and dry density tests, Atterberg limit tests and particle-size analysis were carried out on the samples. The maximum dry density and the optimum moisture contents of the samples are 19.20kN/m 3 and 19.3% respectively, indicating non-cohesive soils that show uniform settlement when loads are imposed on them. The Coefficient of Uniformity (CU) of the samples computed from particle-size distribution curves ranged from 1.50 to 1.85, indicating poorly graded soils that are not good sub-base materials. The liquid limit (LL), plastic limit (PL) and plasticity index (PI) ranged respectively from 29.5 to 41.3%, 12.2 to 36.4% and 4.10 to 29.1. These values strongly suggest the possibility that swelling clay mineral like montmorillonite may be contained in the soil. On the basis of the results of this study, the soils in the area are expansive in nature and this is responsible for the collapse of buildings observed in the area.

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