Aspects of weakening in granular assemblies

TL;DR

This paper investigates the behavior of large 2D granular assemblies under increasing stress, revealing complex dynamics in sliding contacts and stability that challenge previous assumptions.

Contribution

It provides new insights into the relationship between sliding contacts and stability in granular materials through detailed numerical simulations.

Findings

Number of sliding contacts initially rises linearly with stress

Plateau and decrease in sliding contacts occur before peak stress

Behavior of sliding contacts is not directly linked to stability

Abstract

We study numerical simulations of large (N~10^4) two-dimensional quasi-static granular assemblies subjected to a slowly increasing deviator stress. We report some peculiarities in the behavior of these packings that have not yet been adressed. The number of sliding contacts is not necessarily related to stability: first the number of sliding contacts rises linearly and smoothly with the applied stress. Then, at approximately half the peak stress, the increase slows down, a plateau develops, and a decrease follows.