Behavior of grains in contact with the wall of a silo during the initial instants of a discharge-driven collapse

TL;DR

This study experimentally investigates the initial moments of silo discharge, highlighting the role of static friction evolution in predicting collapse, with focus on deformable and rigid wall silos.

Contribution

It introduces a criterion for the maximum time before collapse onset and emphasizes the importance of static friction evolution in silo stability.

Findings

Collapse always occurs before grains adjacent to the wall slide down.

Static friction evolution toward maximum mobilization is crucial for collapse.

A new criterion predicts the maximum time before silo collapse.

Abstract

We study experimentally gravity-driven granular discharges of laboratory scale silos, during the initial instants of the discharge. We investigate deformable wall silos around their critical collapse height, as well as rigid wall silos. We propose a criterion to determine a maximum time for the onset of the collapse and find that the onset of collapse always occurs before the grains adjacent to the wall are sliding down. We conclude that the evolution of the static friction toward a state of maximum mobilization plays a crucial role in the collapse of the silo.