Return period calculation and passive structure design at the Taconnaz avalanche path (France)

• Published in: Annals of Glaciology
• Main Authors: Naaim, M., Faug, T., Naaim Bouvet, F., Eckert, Nicolas
• Other Authors: Érosion torrentielle, neige et avalanches (UR ETGR (ETNA)), Centre national du machinisme agricole, du génie rural, des eaux et forêts (CEMAGREF)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2010
• Subjects: TACONNAZ; [SDE]Environmental Sciences; Annals of Glaciology
• Online Access: https://hal.inrae.fr/hal-02592532; https://doi.org/10.3189/172756410791386517

International audience This paper aims to show how recent knowledge developed in the field of avalanche research can be used for a real case study, the Taconnaz avalanche path, where passive structures already existed but had to be improved. First a morphological analysis of the site is done and historical data are analysed. Second, each recorded event is back-calculated using a numerical model of dense-flow avalanches. For each surveyed avalanche, parameters at the entry of the runout zone upstream of the defence structures are defined. Third, a statistical analysis of these parameters allows characterization of 100 year return period events. Fourth, physical and numerical models of dense avalanches interacting with defence structures are combined in order to design the most effective passive structure able to contain the reference scenarios. Finally, physical and numerical modelling of the interaction between the powder avalanche and the designed defence structure is performed, to show that the proposed improvements do not increase the residual risk due to the powder part in areas downstream of the defence structures.