GEOTECHNICAL ASSESSMENT AND FOUNDATION DESIGN RECOMMENDATIONS FOR THE PROPOSED ENGINEERING STRUCTURE: A CASE STUDY OF WARRI- SOUTH LOCAL GOVERNMENT AREA, DELTA STATE
Author(s):Aladin A. Ese, Osisanya Olajuwon Wasiu, Komolafe N. Perpetual, korode Akinjide Isaac
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Abstract
The research offers an evaluation of the geotechnical index properties of the sub-soil at the proposed building site in Agbassa Community, Warri South Local Government Area of Delta State, Nigeria. Four boreholes were drilled at the site, each reaching a depth of 10.0 meters. The study area, which spans 100m x 100m, was thoroughly investigated through both field studies and laboratory testing. The results reveal that the sub-soil consists of 3 meters of high plasticity clay with high moisture content, overlain by 4 to 5 meters of silty sand that transitions to fine to coarse sand down to a depth of 10 meters. The sand’s textural composition indicates a coefficient of uniformity ranging from 2.01 to 2.04. According to the Unified Soil Classification System, the sand is classified as SM (Silty Sand). The grain size, according to British Standard Sieve Sizes, ranges from 0.06mm to 10mm, showing that the sand is uniformly graded. Further laboratory tests classified the soil as Silty Sand (SM) and the clay as CH under the Unified Soil Classification System. Analysis of geotechnical parameters such as Kv, Cv, Mv, and pressure-depth relationships indicates that the sub-soil is highly compressible with low porosity. The ultimate bearing capacity of the soil ranges from 257.9kN/m² to 341.58 kN/m², with allowable bearing pressures between 85.97kN/m² and 113.86kN/m². Based on these findings, it is recommended to use a long strip foundation for the proposed structure, as it is both adequate and economical. The scope of the work included drilling four boreholes, collecting samples, and assessing the soil’s suitability for the intended construction project.
KEYWORDS:
Keywords: Geotechnical indices, Sub soil investigation, Foundation design, Unified Soil Classification System