In situ creep properties in ice-rich permafrost soil

1987 ◽  
Vol 24 (5) ◽  
pp. 183
Keyword(s):  
Permafrost Soil ◽  
Creep Properties

In situ creep properties in ice-rich permafrost soil

1986 ◽  
Vol 23 (4) ◽  
pp. 504-514 ◽  
Author(s):  
K. W. Savigny ◽  
N. R. Morgenstern
Keyword(s):  
Canadian Arctic ◽  
Permafrost Soil ◽  
Creep Properties ◽  
Factors Affecting ◽  
Naturally Occurring ◽  
Permafrost Soils ◽  
Bear River ◽  
Creep Deformations ◽  
Significant Factors

An in situ analysis of naturally occurring creep has been carried out at the proposed Canadian Arctic Gas pipeline crossing of Great Bear River in the Northwest Territories. This is the third of four papers that describe the study. The borehole inclinometer system and monitoring procedures used to determine in situ movement are described. Significant factors affecting the accuracy of the system are assessed. External factors causing movement of the inclinometer casing are also assessed and movements caused by these factors are separated from natural ground movements. The magnitude and nature of naturally occurring creep deformations are discussed. Key words: Mackenzie Valley, pipelines, slopes, permafrost, soils, geotechnical, inclinometers, creep.

In Situ Deformation of Silicon Cantilever Under Constant Stress as a Function of Temperature

2014 ◽  
Vol 5 (2) ◽  
Author(s):  
Ming Gan ◽  
Yang Zhang ◽  
Vikas Tomar
Keyword(s):  
Strain Rate ◽  
Surface Stress ◽  
Temperature Dependent ◽  
Creep Properties ◽  
Uniaxial Creep ◽  
Measuring Surface ◽  
Silicon Cantilever ◽  
Uniaxial Compressive Stress ◽  
In Situ Deformation

This research reports in situ creep properties of silicon microcantilevers at temperatures ranging from 25 °C to 100 °C under uniaxial compressive stress. Results reveal that in the stress range of 50–150 MPa, the strain rate of the silicon cantilever increases linearly as a function of applied stress. The strain rate (0.2–2.5 ×10-6s-1) was comparable to literature values for bulk silicon reported in the temperature range of 1100–1300 °C at one tenth of the reported stress level. The experiments quantify the extent of the effect of surface stress on uniaxial creep strain rate by measuring surface stress values during uniaxial temperature dependent creep.

Borehole penetration and expansion devices for ice testing

1996 ◽  
Vol 23 (1) ◽  
pp. 157-164 ◽  
Author(s):  
Branko Ladanyi
Keyword(s):  
Special Kind ◽  
Strength Properties ◽  
Theoretical Interpretation ◽  
In Situ Testing ◽  
Cone Penetration ◽  
Creep Properties ◽  
Pilot Hole ◽  
Expansion Test ◽  
Sharp Cone

The paper presents two methods for in situ testing of strength and creep properties of ice, together with their theoretical interpretation and typical results. The two methods which are relatively new in this area of application, are the stress-controlled cone penetration test (CPT), and the sharp cone test (SCT). The CPT has been shown in the last few years to be an excellent tool for both ice quality profiling and ice creep and strength properties determination. The test can be used for penetrating vertically through an ice sheet, or laterally into an ice wall in a trench. The SCT is a special kind of borehole-expansion test. The method consists in pushing a smooth, low-angle, conical indentor into a predrilled conical portion of a borehole, which ends with a smaller diameter pilot hole. The creep properties of ice are then deduced from the relationship between the applied load, time, and cone penetration, which is directly related to the hole expansion. Key words: ice, creep, strength, in situ testing, cone penetration, borehole expansion, sharp cone.

The creep of ice measured with the pressuremeter

1988 ◽  
Vol 25 (2) ◽  
pp. 250-261 ◽  
Author(s):  
B. H. Kjartanson ◽  
D. H. Shields ◽  
L. Domaschuk ◽  
C.-S. Man
Keyword(s):  
Key Words ◽  
Creep Deformation ◽  
Primary Creep ◽  
Test Results ◽  
Compression Tests ◽  
Creep Properties ◽  
Natural Stress ◽  
Natural Temperature ◽  
Stress Environment

The pressuremeter has the potential to measure the creep parameters of ice in situ, that is to say, in the field, in ice at its natural temperature and natural stress environment, and in ice that has not been disturbed by sampling and handling. To prove that the pressuremeter can in fact be used to measure creep properties, a series of pressuremeter tests were run in the laboratory in poly crystalline ice at −2°C. It was found that (1) the particular pressuremeter used maintained an ability to measure creep deformation accurately over a period of 7 weeks, (2) the test results agree for the most part with the findings of other investigators who have used uniaxial compression tests, and (3) the pressuremeter brings into question at least one of the more common assumptions regarding primary creep. Key words: ice, freshwater, creep, pressuremeter.

Creep behaviour of undisturbed clay permafrost

1986 ◽  
Vol 23 (4) ◽  
pp. 515-527 ◽  
Author(s):  
K. W. Savigny ◽  
N. R. Morgenstern
Keyword(s):  
Creep Behaviour ◽  
Canadian Arctic ◽  
Time Behaviour ◽  
Frozen Soils ◽  
Creep Properties ◽  
Naturally Occurring ◽  
Bear River ◽  
River Site ◽  
Pipeline Crossing

An in situ analysis of naturally occurring creep has been carried out at the proposed Canadian Arctic Gas pipeline crossing of Great Bear River in the Northwest Territories. This is the last of four papers that describe the study. Creep properties of natural and reconstituted frozen soils are briefly reviewed. A laboratory programme to measure creep properties of undisturbed ice-rich glaciolacustrine clay samples from the Great Bear River site is described in detail. The results are analysed to determine empirical parameters for constitutive equations that describe the stress–strain–time behaviour of the material. Key words: Mackenzie Valley, pipelines, slopes, ice-rich, soils, permafrost, geotechnical, creep, laboratory.

scholarly journals The Genome Sequence of Psychrobacter arcticus 273-4, a Psychroactive Siberian Permafrost Bacterium, Reveals Mechanisms for Adaptation to Low-Temperature Growth

2010 ◽  
Vol 76 (7) ◽  
pp. 2304-2312 ◽  
Author(s):  
H�ctor L. Ayala-del-R�o ◽  
Patrick S. Chain ◽  
Joseph J. Grzymski ◽  
Monica A. Ponder ◽  
Natalia Ivanova ◽  
...  
Keyword(s):  
Amino Acid ◽  
Low Temperatures ◽  
Permafrost Soil ◽  
Membrane Composition ◽  
Terrestrial Environment ◽  
Subzero Temperatures ◽  
Shock Proteins ◽  
Siberian Permafrost

ABSTRACT Psychrobacter arcticus strain 273-4, which grows at temperatures as low as −10�C, is the first cold-adapted bacterium from a terrestrial environment whose genome was sequenced. Analysis of the 2.65-Mb genome suggested that some of the strategies employed by P. arcticus 273-4 for survival under cold and stress conditions are changes in membrane composition, synthesis of cold shock proteins, and the use of acetate as an energy source. Comparative genome analysis indicated that in a significant portion of the P. arcticus proteome there is reduced use of the acidic amino acids and proline and arginine, which is consistent with increased protein flexibility at low temperatures. Differential amino acid usage occurred in all gene categories, but it was more common in gene categories essential for cell growth and reproduction, suggesting that P. arcticus evolved to grow at low temperatures. Amino acid adaptations and the gene content likely evolved in response to the long-term freezing temperatures (−10�C to −12�C) of the Kolyma (Siberia) permafrost soil from which this strain was isolated. Intracellular water likely does not freeze at these in situ temperatures, which allows P. arcticus to live at subzero temperatures.

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