The Influence of Snow Quality on the Breaking Strength

Departm ent of phys,cs,Faculty of Educa11on Unilersity Fukushlma JaPa?1960 ABSTRACT The breaking strengths of snow were measured by the new teste"S Which had been made by the author.and were respectively expressed by the funCl1o"lot Snow density O" Snow hardness one special merit of the apparates was separately devlced fo" the eXC1し1SIVe use Of low density snow and high density snow,so that the extensive region from 2.0g/Cm2to1.300g/Cm2in the strength were measured by the author. lt was clear from the results f the measurmentsthatthegreateststrengthwaSthe tensile St"ength, the shear strength was about50 percents of the tensile strength and the Comp"eSSIVe St"engthWaS about30percentswhjlejt was concluded by the comparison of strerlgthsof the equldenSlty Snow that the strength of new snow or true grained snow was the greatest,the St"engthOf g"amed Snow was about50percentsof1t and the strength of wet snow was about25 Pc"Cents. l. Introduction In order to explain the growth mechanism of avalanche,it Is necessary to know the b"caking phenomena of snow The study of the breaking strength of deposited snow is being Continued steadily by many scholars since about 1940.But snow is a fragihty material and the handling Is very difficulty,moreover the strength is delicacy changed by the aCCele"at1onOf aPPling force,so that the achievement ls not very notable considering the effort put Into the "eSea"eh・ Reports of the strength of new snow have specially not been published to date,and the g"OWth mechanism of the avalanche of surface layer have not been cleared. The expenmentalapparatesof snow must be made simply and portably because the meaSu"- ments are mostly carried out in the field.It were made by the author that th"ee Simple teste"S for the exclusive use of low density snow,and the tensile,shear and compressive st"ength We"e respectively measured toalevelof2.0g/cm2.Tree testers for the exclusive use Of high density snow were also made and the large strengths were measured.A breaking Phenomenon IS Sen- sitive to each construction of matters,the measured values of strength we"e COnSide"ably dif- ferent even on the snow of similar qualities,and the average of three measl_1"ementS Was taken up In this study During the mounthsof Jan.,Feb.and Mar.from1974 to 1977,these field mea・ surements were carried out at the breast of Mt.Azuma which is about 1,000m in elevation and located approxjmatly15km west of Fukuhima Clty.The number of the samples We"e about 400,and the data were analyzed by a computer. From the measurements as described above and a statistical treatment,the following "eSultS had been cleared In this paper.The each strengthσwas expressed by the Snow densityρIn a