WIT Press


Experiments On A Dry Granular Avalanche Impacting An Obstacle: Dead Zone, Granular Jump And Induced Forces

Price

Free (open access)

Paper DOI

10.2495/FSI110061

Volume

115

Pages

10

Page Range

53 - 62

Published

2011

Size

3,064 kb

Author(s)

P. Caccamo, T. Faug, H. Bellot & F. Naaim-Bouvet

Abstract

This work describes small-scale laboratory tests on dry granular avalanches. Avalanches flow down a channel and impact a wall-like obstacle. A deposit generates upstream of the obstacle and plays an important role in the definition of the total mean force induced on the obstacle by the flow. The estimation of this force is crucial to design efficient protection structures against snow avalanches. Keywords: granular, avalanche, obstacle, force, stagnant zone, laboratory tests. 1 Introduction Mountainous areas have often to take into account the snow avalanche hazard. Protection systems are designed even to prevent the flow to start (active protection) or to protect goods once the avalanche released (passive protection). Passive protection can be done by stopping the flow (catching dams), by deviating its course (deflecting dams) or by spreading the flow and dissipating its energy (breaking mounds). The optimal solution, for passive defence, depends on the location in the run-out zone and the shape of protection structures and on the force they have been designed to support. When a snow avalanche impacts an obstacle, a deposit generates upstream of the obstacle and plays an important role in the definition of the total mean force induced on the obstacle by the flow. This study aims at investigating the behavior of this deposit and its evolution from the beginning to the end of the flow. In Section 2 the experimental approach is introduced. First, an overview on the experimental device and on previous studies carried out on the same device is given, then the new adopted measurement techniques are described. Section 3 presents obtained results in terms of the

Keywords

granular, avalanche, obstacle, force, stagnant zone, laboratory tests