Study of Swelling Potential Soil in Diwaniya City Based on Previous Empirical Equations

AI-Diwaniya city is within the Mesopotamia plain lands with clay and silt character, the high shallow groundwater level about (0.60-1.55) m from the ground level is one of its features. Revealed the properties of soil and groundwater serious problems that occur to buildings and roads in the city, as a result of soil expansion and contraction. To understand the problem, ten boreholes were drilled, field information was recorded and the examination was conducted. The results showed that the clay percentage (11 % −67 %), Plasticity Index (15 %-35 %), and Soil activity (Ac %) is low to moderately active. Four empirical equations from previous works were used to estimate the potential soil swelling, and evaluate the relationship of the physical properties of the soil with the swelling potential. All samples collected from Diwaniya city showed that the soil had low to medium swelling potential, it's possible that it'll be risky for lightweight structures at medium swelling potential. Also, the relationship between swelling potential (Sp %) and plasticity index (PI %) is strong and acceptable, converse the relationship between swelling potential (Sp %) and clay content (Cc %) was weak. This indicates that swelling soil depends on the quality of the mineral present in clay and does not depend on clay percentage, as the type of mineral that appeared in this study is Kaolinites, and Illites according to the plasticity chart of Diwaniya soil samples. Groundwater level is effective in deformations. For this, it is necessary to plan the construction according to groundwater level of the city, as it affects the swell and shrinkage soil.