Dense avalanche numerical modeling interaction between avalanche and structures

Applications of the Saint Venant equations were extended to rapid gravity flows of geophysical fluid with a non-newtonian behavior such as snow avalanches. This paper presents a numerical and physical approach for snow avalanches considered as a granular material. The mathematical equation system is numerically solved. In order to validate the numerical modeling, a reduced scale model is built. The materials are retained behind a dam by a rapid opening gate. The downhill slope is divided into two sections: a steep slope with a channeled flowing zone and a section with an abrupt widening with a slope angle of zero degree. Several experiments have been done with various volumes of different materials. The following parameters were measured in each experiment: 1) the evolution of the height and the forces in three locations along the flowing zone, 2) the velocity field at the surface of the avalanche, and 3) the mapping of the deposition zone. The whole experiments have been numerically reproduced. Engineers in charge of the protection against dense avalanches, increasingly recommend the construction of protection devices whose function, at the end of the flow zone, is to dissipate the avalanche energy. The last section of this paper deals with an attempt of efficiency evaluation of these structures using numerical modeling