An instrumented structure to measure avalanche impact pressure: Error analysis from Monte Carlo simulations

Avalanche impact pressure on a flat surface has been quantified by full-scale experiments performed at the Lautaret avalanche test site (France). An inverse analysis method is used to reconstruct the pressure applied on this instrumented structure from the deformations recorded during the impact. The deformation-to-pressure transfer function of this large sensor is determined by analytical modelling and is used to quantify the pressure of an artificially released avalanche on the structure. Advanced sensitivity and error analyses are used to determine the uncertainty of the reconstructed pressure. First the uncertainties of the different parameters and processes involved are identified and estimated in the deformation-to-pressure transfer function through probability distributions. Then the sensitivity of the reconstructed pressures to these parameters is investigated to identify the most important parameters. Finally, the distribution of the uncertainty in terms of the probability density of the total error in the pressure is estimated using Monte Carlo simulations. Results are discussed on the basis of the drag coefficient to Froude number dependence and compared with previous avalanche data.