Snowpack effects induced by blasts: experimental measurements vs theoretical formulas.
Abstract
To analyse the response of snowpack to explosives and the induced artificial trigger- ing of avalanches, an experimental campaign has been realized during the Winter 2010 in Montero- saSki resort - Gressoney La Trinite (AO- Italy). Two different explosives have been tested (dynamite and emulsion); 24 charges were separately detonated at different elevations from the snowpack (on the snow surface, at 0.5 m, 1 m, and 0.5 m below the surface). The measurements of the craters dimensions induced by the different blasts in the snowpack have been performed, coupled with the pre and post snowpack survey. In this paper, the correlation between geometry of the craters (maximum and minimum diameter and depth) and blasts (type of explosive, change and elevation) parameters is analysed and the em- pirical formulas usually used to design the shots on the snowpack are tested. From the energy point of view, a comparison between dynamic criteria given by different kinds of explosive, charges and elevation and static one is done to understand the influence of artificial trigger- ing in the snowpack stability. The aim of the paper is to define the critical explosive charge: the best agreement between mass of explosive and detonation height to induce an artificial trigger of avalanches.