Swelling Behaviour of Expansive Shales from the Middle Region of Saudi Arabia

Severe and widespread damage in residential buildings, sidewalks and pavements in various parts of the middle region of Saudi Arabia is caused by the development of heave and swelling pressure in the expansive shales in the region. This paper presents the problems and the geotechnical and physicochemical properties of the tested shales. The swelling potential was determined using various methods. Swell tests were conducted under different loading conditions and following different procedures to quantify the amount of vertical swell and swelling pressure. The conventional one-dimensional oedometer swell tests were performed using three different procedures, namely, free swell, constant volume swell and swell overburden. In addition, swell tests were performed in the stress path triaxial apparatus. Tests under different vertical stresses and confinements were conducted. Vertical swell and swelling pressure obtained from the various methods were compared. The reliability of the different methods for estimation of swelling potential is discussed.