Evaluation and Comparison of Various Methods for Determining Suction Compression Index for Oklahoma Soils

Abstract

Suction Compression Index (?h) is an important parameter in characterizing expansive soils and predicting their volume change (shrinking and swelling) behavior. There are various methods available to estimate and measure ?h. In this research, empirical equations to estimate ?h, which use coefficient of linear extensibility (COLE), are discussed and compared with ?h estimated from index properties of soils such as liquid limit, plasticity index and fine clay content. Values of these soil properties were obtained from USDA NRCS database. Results of the analysis show that ?h values obtained from index properties are much higher than the values obtained from COLE. This data is also used to classify Oklahoma soils according to their expansion potential based on COLE and PI. Finally with the help of the estimated ?h values contour maps for Oklahoma are prepared, which can be used by practicing engineers to obtain value of suction compression index.