Instabilities in alpine permafrost: strength and stiffness in a warming regime
Instabilities in alpine permafrost: strength and stiffness in a warming regime:

Global climate change is contributing to hazards to infrastructure in cold regions, as engineers try to quantify uncertainties through a risk-based consideration of sensitivity and consequences, and thereby to mitigate the risks arising from permafrost degradation. A gradually rising Mean Annual Air...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
1. Verfasser: Yamamoto, Yuko (VerfasserIn)
Format: Elektronisch E-Book
Sprache:English
Veröffentlicht: Zürich vdf Hochschulverlag 2015
Ausgabe:1st ed
Schriftenreihe:Veröffentlichungen des Instituts für Geotechnik (IGT) der ETH Zürich
Schlagworte:
Blockgletscher
Geotechnik
Hanginstabilität
Kriechbewegung
Permafrost
Online-Zugang:DE-B1533
DE-860
DE-859
Volltext
Zusammenfassung:Global climate change is contributing to hazards to infrastructure in cold regions, as engineers try to quantify uncertainties through a risk-based consideration of sensitivity and consequences, and thereby to mitigate the risks arising from permafrost degradation. A gradually rising Mean Annual Air Temperature, combined with more extreme rainfall conditions and fewer 'freezing degree days', mean that the water phase in soil that has been frozen for many years in the form of permafrost, is likely to thaw and release groundwater into the voids. Since the properties of warm permafrost can change significantly as its temperature rises, climate change can affect not only the thickness of the active layer and the depth of permanently frozen ground, but also the constitutive behaviour of the permafrost layer. This has significance not only for movements and stability in permafrost slopes but also in rock glaciers, which are ice-rich geomorphological landforms.
Furthermore, permafrost degradation is causing changes in land surface characteristics and drainage systems, as warming of rock glaciers leads to accelerated creep. Instabilities may also be triggered as the constitutive properties of permafrot change, either in the form of active layer detachments or at depth through the warming permafrost. Catastrophic debris flows may also occur. Dr Yamamoto has conducted a fundamental and highly innovative experimental investigation into the effect of time and temperature on the creep and shear strength properties of analogue alpine permafrost, under a range of stress conditions that would be experienced in different locations of a rock glacier. She has developed new equipment to maintain the temperature in the frozen soil specimens at ±0.03°C in the previously unexplored range between 0 and -0.5°C, and to record acoustic emissions during creep and shearing.
Furthermore, she has carried out novel micromechanical investigations into the changes occurring in the solid, ice, air and unfrozen water mixture as a result of shearing. The results of the laboratory tests have been used to provide a deeper insight, not only into the constitutive behaviour of frozen soils, but also a greater qualitative understanding of the geotechnical performance of rock glaciers under warming conditions. In addition, she has extended an existing mechanical constitutive model for soils that includes both soil creep and shear behaviour to develop a semi-coupled Thermal-Hydro- Mechanical (THM) constitutive model. The model, when implemented in a finite element package, allows the laboratory element test data to be predicted, which also validates key aspects of her model rather well. This represents a significant step towards achieving quantitative predictions of the influence of temperature variation on the performance of rock glaciers.
Beschreibung:[1., Auflage 2015]
Beschreibung:1 Online-Ressource (514 Seiten)
ISBN:9783728136411

Es ist kein Print-Exemplar vorhanden.

Fernleihe Bestellen Achtung: Nicht im THWS-Bestand! Volltext öffnen

Ähnliche Einträge