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

Abstract

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 characterise the sand's stress-strain response. The results suggest that the sand's small-strain behaviour 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, the peak stress ratio and the critical states. Furthermore, the data is used to examine a stress-dilatancy relationship often incorporated in constitutive models. The characterisation presented herein aims at assisting the efficient calibration of numerical models and provides insight into this sand's behaviour, thus supporting the interpretation of results of physical modelling involving this sand. This paper highlights the importance of characterising sand's behaviour 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 behaviour.

Grading evolution and critical state in a discrete numerical model of Fontainebleau sand

“…7 illustrates a typical result; the response for theσ′ z ¼ 0 stress path is more dilatant than that for theṗ′ ¼ 0 test, which in turn is more dilatant than the conventional triaxial path (σ′ x ¼σ′ y ¼ 0). The observed stress path effect reflects the evolution of p′ during shearing; similar results are reported from laboratory tests on sand (Vaid & Sasitharan, 1992;Azeiteiro et al, 2017).…”

Centrifuge testing of dual row retaining walls in dry sand: The influence of earthquake sequence and multiple flights

“…In both cases, the wall systems were constructed at 1 g using S28 Hostun Sand (Azeiteiro et al, 2017). The sand was poured at I d ≈ 80 − 85 % using the automatic spot pluviator at the Schofield Centre (Madabhushi et al, 2006).…”

“…The progression of the average secant stiffness per cycle is also plotted. Azeiteiro et al (2017) present the results from Bender element tests on Hostun sand at a very similar initial relative density and plot the variation of G max with p . For soil at the mid-depth of the infill the mean confining pressure could vary between 50 − 220 kP a for horizontal stress variations between K A − K P .…”

Effective skeleton stress and void ratio for constitutive modeling of fiber-reinforced sand

“…Therefore, different c values will be used for the FRS (same sand and fiber properties) with different fiber content. Equations (1) and (2) indicate that, at the failure state, the mean effective stress the sand skeleton 'feels' is p þ p c , which is greater than p. This makes the shear strength of FRS higher than that of host sand. One can thus use the following p s and q s to describe the failure of FRS:…”

“…The specific gravity G s is 2.64. The maximum and minimum void ratios, e max and e min , are 1.0 and 0.66, respectively [2]. Polypropylene fibers with a specific gravity G f = 0.91 are used.…”