Creep behaviour of undisturbed clay permafrost

Savigny, K. Wayne; Morgenstern, N. R.

doi:10.1139/t86-081

Cited by 17 publications

(6 citation statements)

References 12 publications

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“…A mass of dirty ice or ice‐rich debris on a slope would be rigid near the surface, but as deviatoric stress increased with depth, the threshold would eventually by surpassed and intense localized shear could occur. This is consistent with many of the observations of pluglike flow in rock glaciers and permafrost slopes reviewed above [ Savigny and Morgenstern , ; Haeberli et al, ]. Dirty basal ice at the bottom of a glacier might be expected, therefore, to accommodate a large fraction of the glacier's motion, particularly where the dirty ice is close to the melting temperature and the overlying ice is cold, as was the case at Urumqi Glacier [ Echelmeyer and Zhongxiang , ].…”

Section: Summary and Implicationssupporting

confidence: 85%

“…For example, landslides and creep in frozen stratified riverbank materials in northern Canada and Alaska were investigated by McRoberts and Morgenstern [], Savigny and Morgenstern [], and Darrow and others [ Darrow et al, ]. In each of these studies, localized slip displacement was found to occur at depth in fine‐grained strata with high unfrozen water content, while in the latter two studies, extensive distributed creep dominated in ice‐rich strata [ Savigny and Morgenstern , , ; Darrow et al, ]. An inclinometry study of deformation of frozen slopes of the Tibetan Plateau also showed distributed creep occurring within ice‐rich soil, and deformation data approximately matched a power law constitutive relation like that used for pure ice [ Wang and French , ].…”

Section: Field Observationsmentioning

confidence: 99%

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Deformation of debris-ice mixtures

2014

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Mixtures of rock debris and ice are common in high-latitude and high-altitude environments and are thought to be widespread elsewhere in our solar system. In the form of permafrost soils, glaciers, and rock glaciers, these debris-ice mixtures are often not static but slide and creep, generating many of the landforms and landscapes associated with the cryosphere. In this review, a broad range of field observations, theory, and experimental work relevant to the mechanical interactions between ice and rock debris are evaluated, with emphasis on the temperature and stress regimes common in terrestrial surface and near-surface environments. The first-order variables governing the deformation of debris-ice mixtures in these environments are debris concentration, particle size, temperature, solute concentration (salinity), and stress. A key observation from prior studies, consistent with expectations, is that debris-ice mixtures are usually more resistant to deformation at low temperatures than their pure end-member components. However, at temperatures closer to melting, the growth of unfrozen water films at ice-particle interfaces begins to reduce the strengthening effect and can even lead to profound weakening. Using existing quantitative relationships from theoretical and experimental work in permafrost engineering, ice mechanics, and glaciology combined with theory adapted from metallurgy and materials science, a simple constitutive framework is assembled that is capable of capturing most of the observed dynamics. This framework highlights the competition between the role of debris in impeding ice creep and the mitigating effects of unfrozen water at debris-ice interfaces.

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Section: Summary and Implicationssupporting

confidence: 85%

Section: Field Observationsmentioning

confidence: 99%

Deformation of debris-ice mixtures

2014

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“…Many types of laboratory tests, for example shearing in axial compression (AC) at CSR, or maintaining CSC, to measure the resulting creep deformations, or under given strain modes, have been performed on frozen soils or Arctic permafrost (Goughnour and Andersland 1968;Sayles 1974;Parameswaran and Jones 1981;Weaver and Morgenstern 1981;Savigny and Morgenstern 1986;Vyalov et al 1989;Ladanyi 1997) to advance and verify theoretical models. Microstructural aspects have been examined and quantified to establish their influence on mechanical properties by Cole (2001).…”

Section: Laboratory Stress Path Testing Equipmentmentioning

confidence: 99%

Multidisciplinary investigations on three rock glaciers in the swiss alps: legacies and future perspectives

Springman¹,

Arenson

Yamamoto³

et al. 2012

Geografiska Annaler: Series A, Physical Geography

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This paper recognizes the contribution of Professor Wilfried Haeberli for his inspiration and leadership in the field of permafrost science and his generous encouragement, both direct and indirect, to the ETH Researchers who have, through him, endeavoured to contribute to this fascinating research area. The multidisciplinary investigations described in this paper have focused on three rock glaciers, Muragl, Murtèl‐Corvatsch and Furggwanghorn, all of which have been subject to a varying degree of prior study, and which are continuing to attract new generations of researchers to understand and explain the processes and predict future behaviour. This paper marks a stage at which it is possible to summarize some advances in the state of the art and associated innovations that can be attributed to early motivation by Wilfried Haeberli and offers a tribute as well as gratitude for his ongoing feedback and advice. Some thoughts on the development of thermokarst due to water ponding and flow, and a conceptual model of geotechnical mechanisms that aim to explain some aspects of rock glacier kinematics, are also introduced.

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“…The parameter A for in situ deformation of glacier ice would be even lower than the Paterson's value [e.g., Hubbard et al , 1998; Gudmundsson , 1999]. The A values for ice‐supersaturated fine soil under steady state creep hardly exceed those of polycrystalline ice [e.g., McRoberts et al , 1978; Savigny and Morgenstern , 1986]. In addition, an increase in debris content strengthens the frozen soil owing to interlocking of soil particles larger than sand size [e.g., Hooke et al , 1972; Nickling and Bennett , 1984].…”

Section: Factors Affecting Deformation Of Ice‐debris Mixturementioning

confidence: 99%

Fast deformation of perennially frozen debris in a warm rock glacier in the Swiss Alps: An effect of liquid water

Ikeda¹,

Matsuoka²,

Kääb³

2008

J. Geophys. Res.

130

131

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[1] Surface movement, internal deformation, and temperature were monitored over 5 years on Büz North rock glacier, a small rock glacier located at the lower limit of the permafrost belt in the Swiss Alps. The permafrost in the rock glacier mainly consists of pebbles and cobbles filled with interstitial ice. Two inclinometers installed at 4 and 5 m depths showed fast deformation with large seasonal and interannual variations, while the permafrost temperatures remained almost at the melting point. The movement of the inclinometers coincided with changes in the surface velocities. The deformation rapidly accelerated during snowmelt periods, whereas it gradually decelerated below a dry snow cover in winter. The frozen debris was more deformable than typical glacier ice at the melting point. These phenomena suggest that the frozen debris is permeable to snowmelt water. The fast deformation should result from significant annual relocation of debris particles, which probably creates a network of air voids in the frozen debris that eventually allows water infiltration. The meltwater infiltration accelerates the deformation by reducing effective stress, resulting in the reduced strength of the frozen debris. The refreezing of the pore water, which depends on the cooling intensity in winter, decelerates the deformation. The combination of these processes controls the temporal variations in the deformation.

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Creep behaviour of undisturbed clay permafrost

Cited by 17 publications

References 12 publications

Deformation of debris-ice mixtures

Deformation of debris-ice mixtures

Multidisciplinary investigations on three rock glaciers in the swiss alps: legacies and future perspectives

Fast deformation of perennially frozen debris in a warm rock glacier in the Swiss Alps: An effect of liquid water

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