The first-return times in the dynamics of a three dimensional pile of rice are measured. Furthermore, the 1/f exponent of the avalanche dynamics is determined. These quantities taken together, are used to check general scaling relations for systems with extremal dynamics exhibiting self-organized criticality. We find that τfirst = 1 + a. Furthermore, we discuss the relation of the 1/f a exponen...

We perform experimental measurements of the instantaneous velocity profile of the flowing layer during granular avalanches. In the pile depth, the velocity profile follows a pure exponential decrease in contrast with steady flows that are known to exhibit a well developed upper linear part. The velocity profile in the pile width is a plug flow with two exponential boundary layers at the walls. ...

In many geophysical or industrial applications involving flows of grains, a continuum description would be of considerable help, for example in predicting natural hazards or in designing industrial processes. However, constitutive equations for dry granular flows are still matter of debates 1-10. One difficulty is that grains can behave like a solid (in a sand pile), a liquid (when poured from ...

The shape of a granular pile in a rotating drum is investigated. Using discrete elements method (DEM) simulations we show that the "S shape" obtained for high rotation speed can be accounted for by the friction on the end plates. A theoretical model which accounts for the effect of the end plates is presented and the equation of the shape of the free surface is derived. The model reveals a dime...

We investigate the stability of a granular monolayer composed of spherical grains on an inclined plate. When the tilt angle alpha increases, some reorganizations are observed throughout the pile. The packing fraction rho of the packing evolves by successive jumps. Those discontinuous events precede the collapse of the pile at a critical angle alphac. The occurrence of precursors before avalanch...

Relying on a deep foundation pit project in Beijing, using FLAC3D three-dimensional finite-difference software simulation combined with displacement monitoring data verification method, the excavation and three-pile two-anchor rod support system anhydrous sand pebble stratum are systematically analyzed, summed up variation law of formation stress, internal force soil nail, axial bolt, stress pi...

Using a modified Bak-Tang-Wiesenfeld model for sand piles, we simulate a Casimir-like effect in a granular pile with avalanches. Results obtained in the simulation are in good agreement with results previously acquired experimentally: two parallel walls are attracted to each other at small separation distances, with a force decreasing with increasing distance. In the simulation only, at medium ...