Influence of grain shape on stress-dilatancy parameters

This study experimentally investigates the influences of grain shape and gradation on stress-dilatancy parameters. For this purpose, consolidated-drained triaxial tests are conducted on five different granular materials. Specimens are sheared following two different stress paths; axial compression and lateral extension, in order to monitor the influence of stress path on the investigated problem. For each soil, grain shapes, sizes and stress-dilatancy parameters are experimentally determined. Moreover, available data in literature for other sands are compiled with the data of this study. This allows the investigation of the dependence of stress-dilatancy parameters on gradation and grain shape characteristics. Especially with this study, variations of stress-dilatancy constants with grain characteristics are examined. Statistically significant relationships are obtained for predicting stress-dilatancy parameters as functions of average grain shapes. On the other hand, influences of stress path and gradation on stress-dilatancy response are experimentally considered. Finally, compiled and determined data used in the development of the relationships are provided in the form of tables. Graphic abstract