Undrained shear of plastic soils under suction

Abstract

From the very beginning of the soil mechanics the interest for understanding the role of the pore water pressure is evident. In fact, the role of pore water pressure has been investigated even earlier by the agronomic sciences, which prepared a strong base for us. It has been a challenger to bring to practice the entire framework that has been developed for unsaturated soils. The primary purpose of this paper is to discuss undrained shear the behaviour of plastic soils, when the pore water pressure is negative and even under tension, in order to establish a relation between some fundamental characteristics of the soils with the undrained shear strength for plastic soils, and in particular for a residual compacted soil. Data from different type of soils are presented and specifically from a residual soil. Results from triaxial tests demonstrate that suction developed by unloading and by drying the specimen may produce different effects on the undrained shear strength. The results also indicate that the undrained shear test in unsaturated soils can be a valuable tool to bring theory into practice. © Springer-Verlag Berlin Heidelberg 2013.