A Study on Expansive Clay Soils in Sudan

Abstract

In this research the problems associated with the swelling clays were surveyed and presented with special reference to the expansive soils in Sudan. General literature review covering the clay structure and the identification methods of expansive clays is presented and discussed. Existing testing methods for the swelling properties were surveyed and a comparison of two well known testing methods was carried out. These are the constant volume method and the odometer method. An experimental programme was conducted in order to investigate the effect of the following factors on the swelling pressure and the percentage volume change: - Initial moisture content - Initial dry density - Size and horizontal extent of the layer - Thickness of the layer A heave prediction model based on experimental data was presented. Mineralogical survey of the swelling clays in Sudan was conducted using the X-ray diffraction technique. This technique enabled qualitative and quantitative estimation of minerals presenting the clay of Sudan. Finally the micro fabric structure clay was directly observed using the scanning electron microscope. Features of individual particles of swelling soils were shown at different magnifications.