Call number:
ZSP-201-82/43
In:
CRREL Report, 82-43
Description / Table of Contents:
The radar signatures of ice wedges and wedge-like structures have been investigated for a variety of soil conditions. The radar used for this study emitted short sinusoidal pulses of about 10-ns duration with an approximate center frequency of 150 MHz. Most of the ice wedges existed at depths of about 1 m in a variety of silty and sandy soils with both frozen and thawed active layers. The position of the wedges was usually identified from corresponding surface features. An artificial ice wedge in coarse-grained alluvium was also profiled as well as wedge-like structures of fine silt in a coarse-grained glacial outwash. All wedges and wedge-like structures produced a hyperbolic reflection profile except when an active layer of thawed, saturated silt was present which eliminated returns from the wedges. The peaks of the hyper-bolas were sometimes masked by reflections from the permafrost table or other material interfaces, and multiple hyperbolas occurred at some sites. The dielectric constant of the host medium was often calculated from the linear portions of the hyperbolas and the results were verified by laboratory time domain reflectometry measurements per-formed on field samples. In some cases, hyperbolic profiles originated at several meters depth suggesting that deep ice wedges could be detected in areas of cold permafrost.
Type of Medium:
Series available for loan
Pages:
iv, 19 Seiten
,
Illustrationen
Series Statement:
CRREL Report 82-43
URL:
https://apps.dtic.mil/dtic/tr/fulltext/u2/a124571.pdf
URL:
https://hdl.handle.net/11681/9324
Language:
English
Note:
CONTENTS
Abstract
Preface
Introduction
Background
Objectives and procedures
Equipment used
Radar
TDR
Definitions
Massive ice
Results
Artificial wedge: Norwich, Vermont
Ice wedges in sand: Fish Creek, Alaska
Ice wedges: Prudhoe Bay, Alaska
Ice wedges under thawed fine-grained soils: North Slope, Alaska
Wedge-like soil structures: Ft. Greely, Alaska
TDR measurements
Summary and concluding remarks
Literature cited
Appendix A: Brief discussion of dispersion
Location:
AWI Archive
Branch Library:
AWI Library
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