Geotechnical properties of expansive clay shale in Tabuk, Saudi Arabia

Expansive soils prevail in several parts of Saudi Arabia. Tabuk city, in the northwest, is underlain by a shale formation of Ordovician to Devonian age. Arid climate accelerates the development of expansive clays through desiccation and weathering of the shale. The expansion of the city limits extends to potential areas of swelling and urbanization increases the clay moisture content which leads to soil volume change. This causes significant damage to low-rise buildings and pavements. In this paper, the subsurface conditions and geotechnical properties of the expansive soils in Tabuk are presented. The clay type was identified and its degree of expansion was determined. The swelling parameters were measured utilizing the standard oedometer test and modeled by multiple linear regression. The effect of geological and environmental conditions on the swelling behavior of expansive soils in Tabuk were considered. The modeled swelling values are in good agreement with the measured values.