EFFECT OF PRETEST DRYING AND TESTING PROCEDURE ON ENGINEERING PROPERTIES OF BAHIR DAR RESIDUAL SOILS

Residual soils are natural weathering products of rocks and their properties depend on the degree of weathering. These types of soils, which are found in tropical areas, are commonly used in construction, such as dams, highways, and building materials. The properties of residual soils are influenced by a variety of factors, including the original material, climate, topography, drainage, and the methods used for sampling, testing, and classification. Inadequate soil investigations can lead to inaccurate test results, which may result in flawed designs, project delays, increased construction costs, the need for post-construction repairs, and even construction failures. The engineering properties of residual soils are significantly affected by the drying process and testing procedures. This study evaluated the index properties and chemical composition of Bahir Dar residual soils to assess their suitability for various geotechnical engineering applications. The research found that the engineering properties of these soils were significantly affected by the pretest drying and testing procedures. The study recommends soaking the soil samples in water instead of drying and breaking them down with a rubber mallet, as the current standards allow. Additionally, it was observed that the specific gravity values of the residual soils change not only based on the soil texture and particle size distribution, but also on the drying methods used.