Variability Analysis of the Behaviors of a Lateritic Soil Profile as a Structural Material

Abstract

 Specific gravity variation of soil samples proved their were inorganic nature, hence suitable for construction works.  The soil samples have high plasticity, good shear strength, and bearing ability.  The lateritic soil samples are suitable for subgrade, subbase, and base materials.The desideratum of determining the behavior of the underlying soil on which the foundations will be laid is indisputable. This study evaluates the strength characteristics of lateritic soil material at a new construction site opposite College of Engineering and Engineering Technology (CEET), Michael Okpara University of Agriculture, Umudike (MOUAU). A trail pit was dug taking disturbed soil samples at a depth of 1m, 2m, and 3m for experimental analysis. Laboratory tests on specific gravity, grain size distribution, moisture content, atterberg limits, and triaxial tests were carried out on each sample by the procedure highlighted in BS1377 1990. Inspecting visually, the soil profile was observed to consist of three layers; light reddish, reddish, and whitish at the top, middle, and bottom respectively. The natural water content of the soil samples varied as 9.06+0.00 %, 7.98+0.00 %, and 9.32+0.03 %, while the specific gravity obtained from the test results was 2. 630+0.00 %, 2.634+0.00 % and 2.647+0.00 % at depths 1m, 2m, and 3m respectively. Using the unified soil classification system (USCS), the top, middle and bottom layers were classified as cloud sand (SC). The soil samples have a liquid limit (LL) of 24.5%, 28.8%, 31.0%; plastic limit (PL) of 19.4%, 17.2%, 18.5%; and plasticity index (PI) of 5.1%, 11.6%, and 12.5% at depths 1m, 2m, and 3m respectively. It was observed that the soil index properties vary and are enhanced as the depth of the excavation increases. Furthermore, the value of the cohesion property of the soil is 74.62 kN/m2, 29.70 KN/m2, and 24.65 KN/m2 for samples at 2m, 3m, and 3m depth respectively. The greatest and least cohesion value was noted to be 74.62 kN/m2 and 24.65 kN/m2 for samples at 2m and 3m depth respectively; the maximum and minimum angles of internal friction were 25.52o and 13.67o at depths 1m and 2m respectively. The outcome of this paper showed that the analyzed soil samples are suitable for civil engineering works.