Assessment of Geotechnical Parameters of Lateritic Soil of Jos and Environs, for Civil Engineering Constructions North Central part of Nigeria

Abstract

Due to failures of Civil Engineering structures in Jos and its Environs, Geotechnical parameters of Lateritic soils were carried out in order to determine its engineering properties for civil engineering construction. The methods involved are; reconnaissance survey, site works, laboratory tests based on British Standard (BS) methods and interpretation of the results. The laboratory test of the soils revealed that the Atterberg limit; Liquid limit (LL) ranged from 33.0% to 45.0%, Plastic limit (PL) from 16.23% to 26.37%, and Plasticity index (PI) from 8.63% to 22.67%. The percentage passing from the Sieve analysis ranges from 31.62% to 67.66%. The cohesive strength (c) and angle of internal friction (ø) from direct shear test ranged from 13KN/m2 to 24KN/m2 and 9° to 26°. The values of the Total settlement (Pc) from the Consolidation test ranged from 0.0005m to 0.0019m, Soil pH from 5.2 to 7.8, Specific gravity (SG) from 2.57 to 2.73 and Natural Moisture Content (NMC) from 8.18% to 46.36%. From the compaction test; the Optimum Moisture Content (OMC) ranged from 15.22% to 20.60% and Maximum Dry Density (MDD) from 1.62g/cm3 to 1.84g/cm3. The California Bearing Ratio (CBR) test for the soaked soils ranged from 21.0% to 93.0% and Un-soaked values from 50.75% to 96.61%. The findings reveal that; the geology of the area can be largely classified into granites (Biotite-microgranite, N’gell biotite-granite, Jos-biotite-granite and Aplo-pegmatitic granite-gneiss) and laterites. The geotechnical parameters of the soil are characteristically fair to poor, the strength and deformation of the soil reveals that it can mostly be used as a sub-base materials. The soil is classified as silty-clay, and the area need to be stabilized with cement, sand and gravel before carry civil engineering constructions. The results obtained will serve as base-line information for civil engineering construction in the study area in other to avoid structural damage.