Granular pressure and the thickness of a layer jamming on a rough incline

Laboratoire de Modélisation en Mécanique, UMR CNRS 7607 Boîte 162, Université Pierre et Marie Curie - 75252 Paris cedex 05, France

Received: 6 June 2005
Accepted: 30 November 2005

Abstract

Granular media with a compaction between the random loose and random close packings have very specific features. Among them is the “disorder” pressure which strongly depends on the solid fraction and is pertinent for moving media only. The concept of a granular pressure depending on the solid fraction is not unanimously accepted because dense granular media are often in a frozen state which prevents them from exploring all their possible microstates, a necessary condition for defining a pressure and a compressibility unambiguously. While periodic tapping or cyclic fluidization have already been used for that exploration, we here suggest that a succession of flowing states with velocities slowly decreasing down to zero can also be used for that purpose. And we propose to deduce the pressure in dense and flowing granular media from experiments measuring the thickness of the granular layer that remains on a rough incline just after the flow has jammed.