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  • 1
    Series available for loan
    Series available for loan
    Wilmette, Ill. : Snow Ice and Permafrost Research Establishment, Corps of Engineers, U.S. Army
    Associated volumes
    Call number: ZSP-202-18
    In: Research report / Cold Regions Research and Engineering Laboratory, 18
    Description / Table of Contents: Summary: Various strength properties of naturally compacted high-density snows, in the density range of from 0.40 to 0.75 g/cm^3, are reported. Test results are given for: unconfined compression; unconfined and confined double shear; ring, flexural, and centrifugal tensile strength; torsional shear; and work of disaggregation. The work of disaggregation per unit volume was related to crushing, tensile, and shear strength at various lateral pressures, using the same empirical relationship. The results of the various tests measuring the tensile strength of the snow compare favorably with each other. An attempt was made to use the direct shear strength results in Coulomb’s equation for the determination of Mohr’s envelope of rupture for snow. These tests yield higher values than those obtained in unconfined compression tests. However, angles of internal friction obtained considering Mohr’s envelope to be straight line seem to agree with measurements taken on an unconfined compression specimen.
    Type of Medium: Series available for loan
    Pages: 19 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 18
    Language: English
    Note: CONTENTS Page Preface Summary Introduction Temperature correction factors Crushing strength Tensile strength · Shear strength Torsional shear strength Work of disaggregation of snow Angle of internal friction and apparent unit cohesion Discussion of results References
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  • 2
    Series available for loan
    Series available for loan
    Wilmette, Ill. : Snow Ice and Permafrost Research Establishment, Corps of Engineers, U.S. Army
    Associated volumes
    Call number: ZSP-202-47
    In: Research report / Cold Regions Research and Engineering Laboratory, 47
    Description / Table of Contents: Summary: Various mechanical properties such as strength, elastic modulus, and density of TUTO tunnel and ramp ice were determined. Results of unconfined compressive strength, ring tensile strength, and flexural strength tests are given. Photographs of included bubbles and grain size and shape are shown for each of six types of ice tested. Petrofabric diagrams for each type of ice are included. No significant differences in strength were found between horizontal and vertical cores in the ice tunnel, although differences between types of ice are noted. Crushing strength values found for tunnel ice generally fit the empirical equation relating crushing strength to density which was found for high-density snows (Butkovich, 1956a). However the values for ramp ice do not fit the equation when the average density values are used, probably due to the layering. The empirical equation relating ring tensile strength to density of high-density snows (ibid.) gives results approximately 20% greater than those obtained for tunnel ice. It appears that grain size influences the results. Ice with large grains consistently gives lower values. Flexural strength of the ramp ice is about half that of the tunnel ice. Comparing these results with the ring tensile values leads to the conclusion that the beams tend to fail in the lowest-density (mostly bubbly) bands. Temperature curves as a function of depth into the wall and along the tunnel length are presented. A 30-day study of deformation in a 100 x 30 ft room at 650 ft. into the tunnel indicated that the room is closing primarily by a block action, with rates of closure being less only very near the walls.
    Type of Medium: Series available for loan
    Pages: iv, 17 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 47
    Language: English
    Note: CONTENTS Preface Summary Introduction Strength Crushing strength Ring tensile strength Flexural strength Static modulus of elasticity Dynamic modulus of elasticity Density of tunnel and ramp ice Tunnel temperature measurements Crystal size, bubble size, and ice fabrics Deformation measurements Discussion of strength test results References
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  • 3
    Series available for loan
    Series available for loan
    Wilmette, Ill. : Snow Ice and Permafrost Research Establishment, Corps of Engineers, U.S. Army
    Associated volumes
    Call number: ZSP-202-56
    In: Research report / Cold Regions Research and Engineering Laboratory, 56
    Description / Table of Contents: Summary: The results of laboratory creep tests in a shear apparatus at -5°C on 2 x2 x 3/8 in. samples of commercial ice, artificial single crystals, and 6 types of ice from the Greenland Ice Cap, at shear stresses of about 0.5-3 kg/cm^2 are reported. Some uniaxial tests were made at stresses from 6-28 kg/cm^2 to supplement the shear tests. Creep data could usually be represented approximately by one or more linear sections on a log-deformation vs log-time plot. The linear sections of the double logarithmic curve imply a creep curve of the form ε=ct^m where ε is the strain. For all samples tested, except single crystals sheared in easy glide, m averaged 0. 5 for shear deformations up to about 1%, and approached unity for more deformation. For single ice crystals oriented for easy glide, m averaged 1.7, implying a strain softening. Single crystals oriented for hard glide behaved similarly to polycrystals, indicating a rate-controlling process such as dislocation climb. For all but single easy-glide crystals, the minimum creep rate was tangent to the deformation curve at the end of the experiment. Creep rates for single easy-glide crystals were several hundred times larger than for the other crystals, the flow laws being similar.
    Type of Medium: Series available for loan
    Pages: iv, 7 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 56
    Language: English
    Note: CONTENTS Preface Summary Introduction Types of ice Experiments Results Creep curves Flow law References
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  • 4
    Series available for loan
    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-202-99
    In: Research report / Cold Regions Research and Engineering Laboratory, 99
    Description / Table of Contents: Summary: A study of how age hardening affects the various mechanical properties of processed snow was made. A description of how the age hardening process is affected by the variables of density, temperature, grain size, and shape is given. An empirical equation relating creep rate to stress, age, and density was obtained. The study also shows that the various mechanical properties are related to age by an exponential function.
    Type of Medium: Series available for loan
    Pages: iv, 12 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 99
    Language: English
    Note: CONTENTS Preface Summary Introduction Experimental facilities Experimental in-place measurements Density and homogeneity of processed snow Ram hardness Temperature measurements Mechanical properties Unconfined compressive strength Stress-strain relationships in unconfined compress ion Creep in unconfined compression Tensile strength Discussion of results References
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  • 5
    Series available for loan
    Series available for loan
    Wilmette, Ill. : Snow Ice and Permafrost Research Establishment, Corps of Engineers, U.S. Army
    Associated volumes
    Call number: ZSP-202-20
    In: Research report / Cold Regions Research and Engineering Laboratory, 20
    Description / Table of Contents: Summary: Investigations on sea ice at Hopedale, Labrador, March 1956, included: small beam tests and in-place cantilever beam tests for flexural strength; ring tensile-strength tests; unconfined compression tests, with stress-strain studies to determine "Young's modulus"; and double shear tests. The results exhibit a great deal of scatter, primarily due to the inhomogeneity of sea ice. Ring tensile strength values range between 3.3 kg/cm^2 and 22.3 kg/cm2 between -2.5°C and -19.1°C. The small beam tests give flexural strength values from 0.5 to 17.3 kg/cm^2 in a similar temperature range. The in-place pull-up cantilever beam tests give flexural strength values of 2.2 to 4.0 kg/cm^2, with much less scatter. Crushing strength values range from 26.3 to more than 107 kg/cm^2 in the range -4.9°C to -18.3°C. Values for Young's modulus obtained from the slope of the straight line portion of the stress-strain curves in compression ranged between 4520 and 10,225 kg/cm^2. There is a temperature dependence, explained by the effect of change in brine content, on sea-ice structure. The double shear tests give values of 7.8 to 34.2 kg/cm^2 in the range -5.5°C to -12.8°C. These are higher than the tensile-strength values. These failures occurred normal to the direction of growth, while the tensile strength was obtained with failure parallel to it.
    Type of Medium: Series available for loan
    Pages: 15 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 20
    Language: English
    Note: CONTENTS Page Preface Summary Introduction Ring tensile strength Flexural strength of small beams Flexural strength of inplace beams Crushing strength Shear strength Discussion of results References
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  • 6
    Publication Date: 1965-02-15
    Print ISSN: 0148-0227
    Electronic ISSN: 2156-2202
    Topics: Geosciences
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