Dominant grains network and behavior of sand–silt mixtures: stress–strain modeling

Abstract

SUMMARY Stress–strain modeling of sand–silt mixtures is important in the analysis and design of earth structures. In this paper, we develop a stress–strain model that can predict the behavior of sand–silt mixtures with any amount of fines content. This model is based on a micromechanics approach, which involves mean‐field assumptions. For the mixtures with low amount of fines, the mechanical behavior is dominated by sand grains network. On the other hand, for the mixtures with high amount of fines, the mechanical behavior is dominated by silt grains network. Using this concept of dominant grains network, the behavior of mixtures with any amount of fines can be predicted from knowing the behavior of sand and silt, alone. We also modeled the critical state friction angle, critical state void ratio, and elastic stiffness for the mixtures as a function of fines content. The applicability of this developed stress–strain model is shown by comparing the simulated and measured results for two different types of sand–silt mixtures with full range of fines content. Copyright © 2012 John Wiley & Sons, Ltd.

Modeling of minimum void ratio for sand–silt mixtures

“…A simple modeling concept of "dominant network" for a packing with two-size particles has been proposed by Chang and Meidani (2013). On this basis, a new model is developed herein for the analysis of minimum void ratio.…”

“…In Chang and Meidani (2013), the change of void volume is assumed to be proportional to the amount of silt added in the mixture, i.e., V v = aV s2 , where a is a material constant. Note that the limit of 'a' is -1 corresponding to the limiting situation where no change of total volume is occurred.…”

“…In Chang and Meidani (2013), the void volume change is assumed to be proportional to the amount of sand added in the mixture, i.e., . Note that is corresponding to the limiting situation that there is no change of void volume during the process of achieving minimum void ratio of the soil mixture.…”

A Simple One-Scale Constitutive Model for Static Liquefaction of Sand-Silt Mixtures

“…Theoretically, the model described above cannot apply to sand-silt mixtures directly, but we can extend the model to model sand-silt mixtures using the mixture theory combining the properties of sand and silt according to their proportions (Thevanayagam, et al 2002;Chang and Meidani, 2013). Some empirical expressions are adopted here to fit the critical state strength and the location of the…”

“…For mixtures with very low fines contents (for example, lower than 10%), or mixtures with very high fines contents (for example, higher than 70%), the critical state friction angles are experimentally found to be almost not changed with the variation of fine content beyond the threshold content( ie.,10% or 70%). For fines contents between 10%-70%, Chang and Meidani (2013) proposed a simple model to express the effect of fines content on the critical state friction angles of mixtures as follows: …”