Karlsruhe fine sand under monotonic and cyclic loads: Modelling and validation

In this study, a large amount of stress-dilatancy data of Karlsruhe fine sand were examined at first, where it was found that the stress-dilatancy behaviour of Karlsruhe fine sand depended on its void ratio and pressure. To capture such state-dependent stress-dilatancy behaviour, the fractional-order dilatancy equation and Li and Dafalias [1]' s dilatancy equation, were adopted and compared. In addition, a kinematic loading surface characterising the loading/unloading directions was proposed, where the current loading surface moved kinematically within the maximum loading surface. Three hardening moduli were defined for virgin loading, unloading and reloading, respectively. Further validation against a series of monotonic and cyclic test results of Karlsruhe fine sand revealed that: models based on these two dilatancy equations can simulate the drained and undrained behaviour of Karlsruhe fine sand under monotonic and cyclic loads. The unloading-induced contractive response and reloading-induced dilative response during drained loading, as well as the butterfly-shaped liquefaction response under undrained loading can be reasonably reproduced. Li and Dafalias [1]' s dilatancy equation had a relatively better match of the stress-dilatancy data.