Unbound aggregates are the most common type of materials used for construction of the base layer of flexible pavements in Iran and worldwide. Due to the lack of binder, the performance of the compacted unbound aggregates is highly dependent on the properties of the gravel (particles remaining on sieve 4.75mm, sand (particles passing sieve 4.75mm and remaining on sieve 0....

The transmission of pressure waves in granular materials is complicated by the heterogeneity and nonlinearity inherent in these systems. Such waves are propagated through particle contacts primarily along the "force chains" which carry most of the load in granular materials. These fragile and ephemeral chains coupled with irregular particle packing lead to the observed heterogeneity. Nonlineari...

Granular materials enjoy vivid motion phenomena that make them highly visually attractive. However, simulating each and every physical grain imposes an extremely high computational cost, due to the stringent resolution requirements. In this paper, we introduce a method for simulating granular media that achieves high visual resolution and high mechanical fidelity at a lower computational cost t...

We present a framework for analysing the rheology of dense driven granular materials, based on a recent proposal of a stress-based ensemble. In this ensemble, fluctuations in a granular system near jamming are controlled by a temperature-like parameter, the angoricity, which is conjugate to the stress of the system. In this paper, we develop a model for slowly driven granular materials based on...

Of the many improvements in the design of highway pavements during the past two decades, it is doubtful that any have been more important to the life and service of the pavement than the incorporation of the granular base course as a design feature. The true significance of the base course can be more thoroughly understood if one considers the merits of this practice. First, the properly design...

A boundary structure is observed in beds of vertically vibrated granular materials separating regions of opposite phase. This structure is investigated and it is identified as giving rise to both a global kink and hexagonal patterns. A global phase diagram of surface patterns on a vibrated bed is presented. c © 1998 Published by Elsevier Science B.V. In recent years, there has been a dramatic s...

The paper presents results of numerical experiments on a large assembly of smooth circular disks. The assembly was subjected to quasi-static biaxial loading at small to moderate strains by using the Discrete Element Method. Unlike the usual particle-based and coordination number approaches, the fabric was locally measured in relation to the shapes and orientations of voids. Deformation was meas...

There have been many attempts to derive continuum models for dense granular flow, but a general theory is still lacking. Here, we start with Mohr-Coulomb plasticity for quasi-two-dimensional granular materials to calculate (average) stresses and slip planes, but we propose a "stochastic flow rule" (SFR) to replace the principle of coaxiality in classical plasticity. The SFR takes into account t...

The macroscopic friction of particulate materials often weakens as the flow rate is increased, leading to potentially disastrous intermittent phenomena including earthquakes and landslides. We theoretically and numerically study this phenomenon in simple granular materials. We show that velocity weakening, corresponding to a nonmonotonic behavior in the friction law, [Formula: see text], is pre...