Setup of an experimental device for high-speed debris flows generating 2D impulse waves

Landslides and debris flows falling into reservoirs, natural lakes, fjords or seas can generate impulse waves, which can be assimilated to tsunami-water waves. Such wave’s behavior can be highly destructive regarding dams and other structures and infrastructures as well as people living along shorelines. Destructive observed past events, such Vajont Dam in Italy (1963) or Lituya Bay in Alaska (1958), are not enough to describe and finally properly prevent the phenomenon. Experimental studies on the topic have been carried out in one-dimensional (1D) and two-dimensional (2D) water basins with a sliding block or sliding granular material. Due to the lack of studies on the effect of granular material falling in a 2D basin and to explore new ranges of governing parameters of experiments, the present research work is being carried out. In the Fluvial-Morphodynamics Laboratory of GITS in the Technical University of Catalonia, a facility to study that phenomenon is set up. The whole project was founded through the project “Debris Flow” (CGL 2009-13039) by the Spanish Ministry of Science and Technology. The system consists of a steep slope flume releasing granular material in a two dimensional basin. The main drawback was to develop a system able to reach high speed mass movement which was achieved building a metallic wheeled box, sliding in rails with a very low roughness. The second issue was to define a system able to measure the velocity of the granular material and its depth, solved processing images of a high speed camera. Finally a grid on the water surface, done by laser sheets, was set. The water surface being filmed and the resulting images successively processed, the produced wave can be measured. All the measurement systems are designed to not distort the process. First results relative on a first set of experiments are presented and preliminary discussed.