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kobvindex_GFZ20201209134041
Format:
viii, 79 Seiten
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Series Statement:
Research report / Cold Regions Research and Engineering Laboratory 88
Content:
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.
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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
In:
Research report / Cold Regions Research and Engineering Laboratory, 88
Language:
English
Keywords:
Forschungsbericht
URL:
https://hdl.handle.net/11681/5867
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