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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-202-66
    In: Research report / Cold Regions Research and Engineering Laboratory, 66
    Description / Table of Contents: Summary: A simple theory is proposed for crack formation and development by soil desiccation on the basis of laboratory experiments utilizing soil samples (Bloomington till) with max particle size of 1 mm diam. held in flat wooden containers. The crack pattern is more dependent on the thickness of the soil sample than on temperature or humidity. Some effect is caused also by differences in the bottom material of the containers. The area of cells made by crack patterns has a log normal size distribution. Total length of cracks decreases with increase in sample thickness. The number of sides of cells also depends on the thickness. Cracking was found to begin from the center of the soil layer and to propagate to the surface or bottom with non-uniform speed.
    Type of Medium: Series available for loan
    Pages: vi, 48, A4 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 66
    Language: English
    Note: CONTENTS Preface Summary Introduction Soil material Soil Preparation of the soil material Containers Temperature and humidity of the air Moisture content and dry density of the soil Experimental procedures and results General procedures Definition of the characteristics of cracking of soil Cracking moisture content Size of cells made by cracking of the soil Length of cracks Number of sides of cells Development of cracks Additional experiments Interfacial fracture markings Method of auxilliary tests on physical properties of the soil Elastic constants of the soil Shrinkage of soil due to desiccation Tests of the adhesion between the soil and the bottom material Results of auxiliary tests Elastic constants of the soil Free shrinkage process of the soil due to desiccation Adhesion between the soil and glass or wood Mechanism of crack formation due to the desiccation of soil Geometric interpretation Mechanical interpretation Conclusions References Appendix: Table of experiments
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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-202-55
    In: Research report / Cold Regions Research and Engineering Laboratory, 55
    Description / Table of Contents: Summary: Experiments were performed to investigate the processes involved in the formation of sorted patterns which occur naturally in unconsolidated sandy gravel deposits covering the edge of the ice cap southeast of Thule, northwest Greenland. Four different glacier ice surfaces were covered with various thicknesses of sandy gravel in order to observe the effect of differential melting on the formation of sorted patterns. The different stages of pattern formation were recorded by photographs taken at 7-day intervals. A thin gravel cover of 2 in. allowed more rapid melting than did a cover of 6 in., with the result that depressions and mounds were formed. Coarse particles were segregated in the depressions by natural sorting of the various particle sizes when set in motion by differential melting and resulting uneven collapse of the gravel cover. The sorting produced well-developed stone rings in three of the areas, caused directly by the differential insulation provided by the gravel cover. In the fourth area a uniform gravel cover over a smooth ice surface produced no sorted nets, although a poorly developed stone stripe was formed in a melt-stream channel. A stone stripe was also formed in a stream channel cut into the ice along the edge of the test area. This stripe was composed of coarse particles which rolled down from the better insulated heights of the test area. It is therefore possible that sorted nets and stripes occurring naturally in the moraine deposits on the edge of the ice cap could have been formed by mechanical sorting induced by differential melting of the ice under a non-uniform layer of sandy gravel.
    Type of Medium: Series available for loan
    Pages: iv, 15 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 55
    Language: English
    Note: CONTENTS Preface Summary Introduction Procedure Preparation of test plots Measurements of ice and gravel surfaces Composition of the gravel covering Results Sorting in a smooth layer of sandy gravel over an uneven ice surface Sorting in a uniform layer of sandy gravel over depressions in the ice surface Sorting in a uniform layer of sandy gravel over a uniform ice surface Sorting in a non-uniform layer of sandy gravel over a uniform ice surface Discussion and recommendations Conclusions References
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  • 3
    Series available for loan
    Series available for loan
    Hanover, NH : U.S. Army Cold Regions Research and Engineering Laboratory
    Associated volumes
    Call number: ZSP-202-105
    In: Research report / Cold Regions Research and Engineering Laboratory, 105
    Description / Table of Contents: Summary: A principle of particle segregation by freezing is presented. It is demonstrated experimentally by using a transparent freezing cabinet in which a sample of distilled water freezes from the bottom upward. In this way the freezing front line travels vertically and the particles are carried against gravity. By using the same material with different shapes (glass beads and broken quartz or glass) it is demonstrated that an important factor in particle migration is the shape of the particle or its contact area with the interface. By testing other materials with different shapes and sizes, it is demonstrated that another important factor is particle size and rate of freezing. Fine particles migrate under a wide range of rates of freezing; coarser ones migrate at lower and more limited ranges of rates of freezing. It is suggested that, for determining frost behavior of soils in permafrost regions, freezing from the bottom upward is a more reliable test than freezing from the top down. Freezing from the bottom more closely approximates freezing of the active layer above permafrost; also, friction with the cylinder testing wall is eliminated. The implication of this principle in engineering and studies of soil genesis in cold regions is emphasized.
    Type of Medium: Series available for loan
    Pages: iv, 8 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 105
    Language: English
    Note: CONTENTS Preface Summary Introduction Experimental procedure Experimental results Conclusions and recommendations References
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  • 4
    Call number: ZSP-202-85,1
    In: Research report / Cold Regions Research and Engineering Laboratory, 85,1
    In: The frost behavior of soils : laboratory and field data for a new concept, Part I
    Description / Table of Contents: Partial summary: Laboratory experiments have been performed with special cabinets in which soil samples, under complete saturation and without surcharges, were subjected to alternate freezing and thawing cycles. Tests included series with both freezing and thawing from the top and with freezing from the bottom and thawing from the top. The soil materials used were well-graded, sandy gravels, the finest one with 14% finer than no. 200 mesh (0. 074 mm).
    Type of Medium: Series available for loan
    Pages: iv, 22 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 85,1
    Language: English
    Note: CONTENTS Preface Summary Introduction to the problem Laboratory data Preliminary experiments Vertical sorting and volume changes produced by cyclic freeze -thaw Volume increase by sorting in straight graded samples without freezing and thawing Field data Vertical sorting of the active layer Correlation between laboratory and field data Conclusion and recommendations References
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  • 5
    Call number: ZSP-202-85,2
    In: Research report / Cold Regions Research and Engineering Laboratory, 85,2
    In: The frost behavior of soils : laboratory and field data for a new concept, Part II
    Description / Table of Contents: Laboratory experiments were performed with a specil closed-system side-freezing cabinet in which completely saturated soil samples were subjected to alternate freeze-thaw cycles without surcharge. A vertical or nearly vertical freezethaw plane was obtained in the side-freezing cabinet. The soil used was a straight graded noncohesive material with 14 finer than the No. 200 0.074 mm mesh sieve. According to frost criterion based only on gradation, the soil would be classified as a never frost-heaving moraine soil or non-frost-susceptible. All experiments were run for 20 and 22 cycles. Freezing rates used were as follows 30.0 mmhr 33.0 mmhr and 4 .0 mmhr. The initial dry density was approximately constant for each test at 1.8 gcm3 or 112.4 lbft3, and complete saturation was maintained in the tests.
    Type of Medium: Series available for loan
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 85,2
    Language: English
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  • 6
    Call number: ZSP-202-88
    In: Research report / Cold Regions Research and Engineering Laboratory, 88
    Description / Table of Contents: Summary: Four ground patterns were investigated by means of trenches cut in the outwash near Thule, Greenland: circular and linear depressions in unsorted material, polygonal troughs in unsorted material, sorted circles, and irregular mounds and depressions of low relief formed in unsorted finer grained material. Correlation is made between surface pattern, grain size and structure of the active layer, and type and distribution of ground ice for the patterns investigated. Classification of the active layer as disturbed, slightly disturbed, and undisturbed is based on the condition of primary depositional bedding and the presence or absence of vertical sorting. Other features of the active layer, depending upon its type, are an accumulation of fines at the bottom of the active layer and on top of stones, and a siliceous calcareous evaporite on the under surface and clean washed coarser particles beneath the larger stones. Fabric analysis of four kinds of ground ice is presented: ice wedge, relict ice, ice mass, and ice lens, as well as analysis of the contact of ice wedges with relict and mass ice. Practical applications, based on the conclusions, are given for the selection of foundation sites and the location of non-frost-susceptible building materials. NOTE: This is a very large file. Please give your browser several minutes to download the file.
    Type of Medium: Series available for loan
    Pages: viii, 79 Seiten , Illustrationen
    Series Statement: Research report / Cold Regions Research and Engineering Laboratory 88
    Language: English
    Note: CONTENTS Preface Summary Introduction Glossary Part 1 : Surface pattern, structure of the active layer, and type and distribution of ground ice in the permafrost Pattern type 1: Circular and linear depressions in unsorted outwash Circular depressions, area 1 Structure of the active layer Ground ice and its relation to surface morphology Linear depressions, area 5 Structure of the active layer Ground ice and its relation to surface morphology Pattern t ype 2 and 3: Polygonal troughs in unsorted outwash and sorted circles or centers of fines Area 3 Structure of the active layer Ground ice and its relation to surface morphology Area 4 Structure of the active layer Ground ice and its relat ion to surface morphology Pattern type 4: Mounds and depressions of low relief in unsorted outwash Area 4a Structure of the active layer Ground ice and its relatiop. to surface morphology Part 2: Ground ice studies Area 1 Lens ice History Appearance of the ice Fabric analysis Wedge ice History Appearance of the ice Fabric analysis Relict ice History Appearance of the ice Fabric analysis Contact between ice wedge and relict ice Ice sockets Area 5 Wedge ice Fabric analysis Relict ice Fabric analysis Area 3 Ice mass History Appearance of the ice Fabric analysis Ice wedge Fabric analysis Contact between ice mass and wedge Appearance of the ice Fabric analysis Summary and conclusions Pattern type 1: Linear and circular depressions in. unsorted outwash Pattern type 2: Polygonal troughs formed in unsorted outwash Pattern type 3: Sorted circles or centers of fines Pattern type 4: Mounds and depressions of low relief in fine-grained unsorted outwash Engineering applications References Appendix A: Associated studies Appendix B : Recommendations for further field and laboratory work Appendix C: Recommendations for field and laboratory techniques
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  • 7
    ISSN: 1365-3091
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: Secondary precipitates (iron oxide, calcite, etc.) are currently observed in cold-climate Pleistocene deposits. Some have micro- and ultrastructures quite different from precipitates of vadose, phreatic and biogenic origin, and seem to have originated by freezing processes. The microstructures of calcite coatings from a Pleistocene cryopediment in the Mendoza Pre-Cordillera, from a Lower Pleistocene cryogenic slope deposit in Western Transbaikalia and from the present active layer in Antarctica are described. They show similar patterns: fibrous crystals often consisting of piles of platelets, some with internal holes, assembled in millimetre-scale fringes on the lower face of clasts. Observational (mainly fabric) evidence confirms that such peculiar crystals are formed during freezing. The features are unknown in other climates and, when found in past sediments, can be diagnostic of cryogenic palaeoenvironments.
    Type of Medium: Electronic Resource
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  • 8
    Publication Date: 1992-04-01
    Print ISSN: 1045-6740
    Electronic ISSN: 1099-1530
    Topics: Geography , Geosciences
    Published by Wiley
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  • 9
    Publication Date: 1991-01-01
    Print ISSN: 1045-6740
    Electronic ISSN: 1099-1530
    Topics: Geography , Geosciences
    Published by Wiley
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  • 10
    Publication Date: 1991-01-01
    Print ISSN: 1045-6740
    Electronic ISSN: 1099-1530
    Topics: Geography , Geosciences
    Published by Wiley
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