Le programme de recherche sur les risques naturels en montagne du contrat état-région Rhône-Alpes. Deuxième partie : érosion et crues torrentielles. Le point sur le programme de recherches relatif aux laves torrentielles

Latest assessment of the research programme on torrential lava

Abstract

Following long periods of rain or violent storms, the soil in the catchment area of mountain torrents is eroded. Sediments resulting from this erosion are partly carried by the torrent. In some exceptional cases, a torrential lava may be formed and in this case sediment concentration is very high and this forms a slide of a mixture with an "intermediate" consistence between saturated soil and a muddy suspension. Studies carried out in collaboration with the CEMAGREF and the IMG related to the rheology of the lava: flow meter tests in existing laboratories: construction of a special flow meter. Two other actions are being considered: experimental study on movements of particles in the fluid; numeric study on the transitional nature of real slips.