updated that figure to include field data de-
veloped by them, as well as the results of
earlier work by Dorr and Jessberger (1983).
That figure is shown here in Figure B4 to which
we have added data from Endo et al. (1990).
STRENGTH
In his discussion of failure, Mellor (1975)
discussed the ambiguity of the term and
adopted the definition that failure is "related
to the maximum deviatoric stress that can be
reached at a given strain rate...". He used this
definition because it does not distinguish be-
tween brittle and ductile cases, and thus ap-
plies across the spectrum of possible failure
modes for snow. However, he presented data
only for the brittle regime (i.e., at high rates of
loading) in uniaxial tension and compression,
and some data for shear from various exper-
iments and from estimates based on the
Figure B5. Uniaxial compressive and tensile strengths of
analysis of avalanche fractures. The data
snow under rapid loading rates from Mellor (1975). Orig-
from Mellor (1975) are shown in Figures B5
inal data (M-compression and M-tension) from Bucher
and B6 to which we have added data from
(1948), Butkovich (1956), Haefeli (in Bader et al. 1939),
later studies by McClung (1977) and Narita
Hawkes and Mellor (1972), Keeler (1969a), Keeler and
(1980). Note that a compilation of in situ
Weeks (1967), Kovacs et al. (1969), Mellor and Smith
measurements of tensile strength of snow
(1965), Ramseier (1963), and Smith (1963, 1965). Addi-
tional data are (A) for strain rates greater than 5 104 s1
has recently been prepared by Jamieson and
Johnston (1990) and has been added to Fig-
from Narita (1980) and (B) the compilation of in situ ten-
ure B5.
sile strength data in Jamison and Johnston (1990).
Figure B6. Shear strength of snow from Mellor (1975).
Original data from Ballard and McGaw (1965), Butkovich
(1956), Haefeli (in Bader et al. 1939), Keeler (1969a), Keeler
and Weeks (1967).
29
Previous Page
