Spatial distribution and variation of the plasticity of soils in Port Harcourt, South Southern Nigeria

Maps illustrating the variance in the plasticity of the soils in Port Harcourt and its surroundings were created using data from 147 soil study reports, primarily the Atterberg Limits, on a scale of 1:5000 meters at depths of 1 to 1.5 meters, 3 meters, and 6 meters. These maps were intended to serve as a rapid reference for land use planning as well as for the planning, designing, and building of civil engineering buildings. Soil samples taken at 1.5, 3 and 6 m depths showed a Natural Moisture Content that clustered around 17.93% with little variation from this average value. At the depth of 1 to 1.5 meters, where the majority of shallow building foundations are positioned, the study's liquid limit results ranged from 22% to 180%, with an average of 45.11%. The average value of the Plasticity index was 22%, with a range of 9.5% to 87%. According to the USCS soil classification, the soils were categorized as CI, CL, and CH, with a few sites having MH-OH. This suggests that the majority of the clays in the Port Harcourt regions are inorganic clays with medium to high plasticity. According to regression analysis, the consistency limits and moisture contents have negligible to marginally significant associations. These engineering geology maps were created to help planners and decision-makers allocate land for civil engineering projects and sustainable land use.