Intrinsic Swelling & Physiochemical Properties Of Swelling Soils From The Sudan

Abstract

Expansive clay soils cover large areas of Sudan, over one third of the Sudan’s one million square miles. These areas include most of the population centers and development project in the Sudan. Extensive damage and distress have occurred to the water lines, sewers, building, roads and other structures located in or on the expansive clay in the Sudan. In some cases, the cost of repairs to or replacement of irreparably damaged structures has exceeded the structures initial cost. This thesis focused on identification and classification of expansive clay soils in the Sudan, to provide warning against expected potential hazards in the future. In this research sixteen samples were collected from different areas in the Sudan, Almanshia, Alnishashiba, White Nile , Dinder, Malakal, Khartoum North, Omdurman Kosti, Heglieg, Medani, Soki, Unity State Gadrif and Damazeen. Mineralogical survey was conducted using the X-ray diffraction technique. This technique enabled qualitative estimation of minerals present . Montmorillonite was found to be the dominant mineral for all samples. An experimental programme was conducted in order to identify the physical properties that affect the intrinsic swelling and the relationship between intrinsic swelling and physiochemical soil properties such as Atterberg Limits and cation exchange capacity. The soil potential for swelling was determined using free swell and swell Percent. The liquid limit (LL), Plasticity Index (PI), Cation Exchange Capacity (CEC), Sand Content (S) and Linear Shrinkage (LS) are found to correlate quite well with intrinsic swelling. The simple Linear Shrinkage test can be used as a good indicator of swell potential.