Critical State-Based Interpretation of the Monotonic Behavior of Hostun Sand

A series of bender element tests and drained and undrained monotonic triaxial compression and extension tests were performed on air-pluviated samples of Hostun sand. Samples were prepared to different initial void ratios, consolidated under various isotropic and anisotropic stress states, and sheared using different stress paths and a wide range of deformations to characterize the sand's stress-strain response. The results suggest that the sand's small-strain behavior essentially depends on the current void ratio and mean effective stress. Within the medium to large strain range, a state-parameter approach in conjunction with the critical-state framework can successfully predict the distinctive states of the sand's monotonic response, namely the phase-transformation, peak-stress-ratio, and critical states. Furthermore, the data are used to examine a stress-dilatancy relationship often incorporated in constitutive models. The characterization presented herein aims at assisting the efficient calibration of numerical models and provides insight into this sand's behavior, thus supporting the interpretation of results of physical modeling involving this sand. This paper highlights the importance of characterizing sand's behavior over the full strain range and shows that accurate predictions of the critical state and small-strain stiffness are crucial to assess other aspects of the sand's behavior.