Design of Snow Avalanche Deflecting Dams : Veränderungen im Natur- und Kulturhaushalt und ihre Auswirkungen : INTERPRAEVENT

2000

15 Lit. Ang.

Unselbständiges Werk

13124

200084955

Extensive effort has been put into improved understanding of avalanche deflection over the last two years. This paper discusses construction of defelcting dams in steep terrain, and gives an in-depth description of the recent design of two deflecting dams in western Norway. The design is based on a computational/empirical approach convenient for practitioners. Trajectories and preliminary run-up heights on the defelcting dam are first calculated using a centre-of-mass model based on the Voellmy-Perla equation. To compensate for thel imitations of a centre-of-mass consideration, the run-up heights are subsequently calibrated utilising observations of six full-scale avalanches in terrain formations acting as "natural defelcting dams". The functionality of the two dams is demonstrated by comparisons between the design criteria and the observations of four major avalanches impacting the two dams shortly after completion. The validity of the method is further demonstrated by comparison of calculated and observed run-up heights for avalanches impacting the deflection dam in Flateyri, Iceland. The observations on the constructed dams are finally used to update the calibaration procedure.