: The understanding of the behavior of rock mass avalanche is the aim of the present work. The first stage of the research consisted of carrying out an experimental campaign with irregular shaped particles in order to generate the dilatancy phenomenon in the particle flow. The experimental results facilitated the elaboration of an original state law taking into account the relevant parameters such as the granular temperature, the dilatancy and the local height in the flow. At the same time, the granular flow was modeled by means of a fluid dynamics software. A compressible two-dimensional mono-fluid description was considered, to which the previous experimental state law was added. The numerical results obtained confirm the feasibility of the homogenezation approach. The second stage of the work is to rigorously identify the different terms appearing in the fluid dynamics equations to obtain a new set of equations allowing the complete motion of a great extent rock mass avalanche.
1 INTRODUCTION
Rock falls constitute a widely spread natural hazard in the mountainous regions all around the world. For example, one can mention the natural disaster which occurred in Italy (Aoste region) during the year 2000. In France, the site of S échilienne (Alps) is under continuous monitoring, since a rock mass of several cube meters is considered to be unstable. The controllability of these phenomena depend on their size. As far as small extent rockfalls are concerned, rock mechanics experts are generally able to propose technical solutions to protect inhabited areas, road infrastructures and industries. On the other hand, huge extent rock avalanches (volume > 1hm3) leads to catastrophic scenarios for which classical rockfall protection structures are inefficient. Therefore, prevention strategies are elaborated by the land authorities in order to reduce the human and means losses when such a disaster occurs.
