X-ray observation of micro-failures in granular piles approaching an avalanche

Abstract

An X-ray imaging technique is used to probe the stability of 3-dimensional granular packs in a slowly rotating drum. Well before the surface reaches the avalanche angle, we observe intermittent plastic events associated with collective rearrangements of the grains located in the vicinity of the free surface. The energy released by these discrete events grows as the system approaches the avalanche threshold. By testing various preparation methods, we show that the pre-avalanche dynamics is not solely controlled by the difference between the free surface inclination and the avalanche angle. As a consequence, the measure of the pre-avalanche dynamics is unlikely to serve as a tool for predicting macroscopic avalanches.

References in corpus (7)

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• Investigating the Geometrical Structure of Disordered Sphere Packings
• Pre-avalanche instabilities in a granular pile
• Contact dynamics in a gently vibrated granular pile
• Intermittent dry granular flow in a vertical pipe
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Cited by in corpus (9)

• Analyzing X-Ray tomographies of granular packings
• Friction vs Texture at the Approach of a Granular Avalanche
• Correction of beam hardening in X-ray radiograms
• Sheared force-networks: anisotropies, yielding and geometry
• Memory of the Unjamming Transition during Cyclic Tiltings of a Granular Pile
• Experimental evidence of ageing and slow restoration of the weak-contact configuration in tilted 3D granular packings
• On the dependence of the avalanche angle on the granular layer thickness
• Bounds on the shear load of cohesionless granular matter
• Local Coulomb versus Global Failure Criterion for Granular Packings