PERMEABILITY OF GRAIN SIZES IN SOIL

This study carried out an investigation on the permeability of grain sizes in soil in Ekosodin, Benin City, Edo State. Due to several collapse of structure in the geographical location and occurence of flooding during the past years, it was essential to investigate if the soil in the area is more or less permeable, To know the most approciate or suitable type of foumdation applicable and the right drainage system to be implemented. The permeability of the soil was tested for by the application of an empirical formula called the kozeny carman equation. This equation is composed of the kozeny carman constant ranging between (0.8 to 1.0), specific surface area, and void ratio. The specific gravity and particle size distribution test was carried out to determine the specific surface area, the moisture content test was also carried out to determine the void ratio of the soil, including the atterberg limit test, the results obtained from the test was used to determine the approximate kozeny carman constant to be applied which was done in Civil/Structural Engineering Laboratory in the University of Benin, Benin City, Edo State. The soil sample used for the various test was taken from Ekosodin with the application of the auger to extract soil sample from four boreholes at 0.5m to 1m respesctively. Through this application the permeability of the soil was determined. The results obtained for the permeability of the soil from the above tests listed, were 1.039×10⁻¹⁰m², 1.002×10⁻¹⁰m²,1.123×10⁻¹⁰m²,1.394×10⁻¹⁰m²,3.797×10⁻¹⁰m²,9.922×10⁻¹¹m², 2.476×10⁻¹¹m², and 6.024×10⁻¹¹m² respectively. Indicating that the soil has a very low permeability. Several mitigation and strategies are recommended, such as soil amendments with coarser materials like sand or organic matter to improve permeability, the installation of drainage systems such as perforated pipes or gravel trenches, and proper land management practices should be implemented in the area, Piles or piers, are strongly recommended to reach stable soil below the water table. Comprehensive drainage systems, including perimeter drains, free-draining backfill, and proper surface grading, are essential regardless of foundation type.