Mechanistic SEM Study and How Organic Matter Affected the Soil's Geotechnical Performance in Abu Al-Khaseeb, Basrah Governorate

This study aims to understand the influence of organic matter on the mechanical characteristics of Abu Al-Khaseeb soil from Basrah Governorate. The study uses Scanning Electron Microscopy as a supporting technique to gain a better understanding of the resulting changes in soil microstructure. In response to the rapid urbanization of the region, combined with the shift from agricultural to residential land use, organic material was affixed to the soil sample at different weight percentages (2%, 4%, 6%, 8%, and 10%). The results of Atterberg’s limits and unconfined compression strength tests showed that the geotechnical strength of the soil decreased as the level of organic matter present in the soil increased, and the soil became more compressible. Formation of a more open and non-uniform pore structure in the soil with enlarged micro-spaces was also observed. The influence of the level of organic matter in the soil on the mechanical and geotechnical characteristics of the soil was clearly illustrated in the results obtained from the tests. Based on these results, it can be stated that the level of organic matter in the soil cannot be neglected in all civil engineering practices and urban development. Considerable levels of organic matter in the soil can result in major reductions in the geotechnical effectiveness of clay soil.