Pressure of snow avalanches against buildings

摘要

The paper aims to analyse the effects of topography and building position on the magnitude of pressure exerted by snow avalanches against buildings, through a structural back analysis and numerical fluid-dynamics. Studying a real snow avalanche impact occurred in 2008 which destroyed a village in Valsavarenche (Aosta Valley - IT), the attention is focused on the avalanche flow deviation caused by the destructive interaction with a first building, which protected part of a second building beyond it. By means of photographical and in situ survey, a detailed description of avalanche geometrical, dynamical and physical properties is outlined. A structural investigation, based both on debris arrangement and on measurements on the undamaged parts of buildings is also carried out. Thus, a back analysis is carried out in order to define collapse dynamics and to estimate the upper and the lower bound of impact pressure. Afterwards, numerical fluid-dynamical analyses are performed to simulate different impact scenarios and to understand the effects of obstacles on avalanche behavior: a qualitative measure of the interactions among buildings, which may mutually protect one another, is obtained.