Prediction of swelling potential of an expansive shale

A reliable estimate of the expected heave represents the most important factor influencing the selection and design of the foundation system which would accommodate the volume change. Several methods have been proposed in the literature for the prediction of swelling potential of expansive soils. In this paper, experiments using various methods to determine the swelling potential of an expansive shale from the middle region of Saudi Arabia were performed to quantify the amount of vertical swell and swelling pressure. Laboratory tests were used to determine the geotechnical and physicochemical properties and mineralogical composition of the tested shale. Swell tests were conducted under different loading conditions and following different procedures. 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 swell potential is discussed. The laboratory test results are compared with field data.Corresponding Author: Professor Abdullah Ibrahim Al-Mhaidib Department of Civil Engineering, College of Engineering, P.O. Box 800, Riyadh-11421, Saudi Arabia. Email: muhaidib@ksu.edu.s