Éléments pour l'étude des projets de travaux contre les avalanches

SUMMARY. ELEMENTS FOR THE STUDY OF PROTECTION WORKSAGAINST AVALANCHE DEVASTATIONS. Protection against avalanche devastations is justifiable of twomethods.The older admits avalanche as unavoidable and strains to palliateits effects.Works of this inspiration are qualified : passive protection worksor defence works.The second method is based upon recent knowledges on snowpurchased by helvetic specialists. This method acts with success oncauses of avalanches. Their formation is prevented by stabilisationworks in the departure area.Works of this inspiration are qualified : active protection works orextinction works.These two methods are successively examined. About defencework, the greater part of the development is reserved for types ofconstructions. Three categories are distinguished : stopping constructions,deviation constructions and slowing constructions. Theconception of this works is still empiric. Advantages and inconveniencesof this types of constructions are briefly indicated.Extinction works are studied more complety. Indications are givenabout formation and location of dangerous areas. Various factors interveningon snow evolution are indicated. Normes of constructionare deducted. Principal types of stabilisation works are describedbut the greater part of the development is point on articulated constructions.Indications are furnished on efforts than constructions areundergoing. A method for calculation of articulated construction isgiven. This type of construction is advised for its efficiency andcheapness .Forest action on avalanches is reminded in conclusion