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dc.contributor.author
Mamot, Philipp
dc.contributor.author
Weber, Samuel
dc.contributor.author
Schröder, Tanja
dc.contributor.author
Krautblatter, Michael
dc.date.accessioned
2018-11-28T08:09:08Z
dc.date.available
2018-11-09T05:04:24Z
dc.date.available
2018-11-28T08:09:08Z
dc.date.issued
2018
dc.identifier.issn
1994-0416
dc.identifier.issn
1994-0424
dc.identifier.other
10.5194/tc-12-3333-2018
en_US
dc.identifier.uri
http://hdl.handle.net/20.500.11850/302237
dc.identifier.doi
10.3929/ethz-b-000302237
dc.description.abstract
Instability and failure of high mountain rock slopes have significantly increased since the 1990s coincident with climatic warming and are expected to rise further. Most of the observed failures in permafrost-affected rock walls are likely triggered by the mechanical destabilisation of warming bedrock permafrost including ice-filled joints. The failure of ice-filled rock joints has only been observed in a small number of experiments, often using concrete as a rock analogue. Here, we present a systematic study of the brittle shear failure of ice and rock–ice interfaces, simulating the accelerating phase of rock slope failure. For this, we performed 141 shearing experiments with rock–ice–rock "sandwich"' samples at constant strain rates (10−3s−1) provoking ice fracturing, under normal stress conditions ranging from 100 to 800kPa, representing 4–30m of rock overburden, and at temperatures from −10 to −0.5°C, typical for recent observed rock slope failures in alpine permafrost. To create close to natural but reproducible conditions, limestone sample surfaces were ground to international rock mechanical standard roughness. Acoustic emission (AE) was successfully applied to describe the fracturing behaviour, anticipating rock–ice failure as all failures are predated by an AE hit increase with peaks immediately prior to failure. We demonstrate that both the warming and unloading (i.e. reduced overburden) of ice-filled rock joints lead to a significant drop in shear resistance. With a temperature increase from −10 to −0.5°C, the shear stress at failure reduces by 64%–78% for normal stresses of 100–400kPa. At a given temperature, the shear resistance of rock–ice interfaces decreases with decreasing normal stress. This can lead to a self-enforced rock slope failure propagation: as soon as a first slab has detached, further slabs become unstable through progressive thermal propagation and possibly even faster by unloading. Here, we introduce a new Mohr–Coulomb failure criterion for ice-filled rock joints that is valid for joint surfaces, which we assume similar for all rock types, and which applies to temperatures from −8 to −0.5°C and normal stresses from 100 to 400kPa. It contains temperature-dependent friction and cohesion, which decrease by 12%°C−1 and 10%°C−1 respectively due to warming and it applies to temperature and stress conditions of more than 90% of the recently documented accelerating failure phases in permafrost rock walls.
en_US
dc.format
application/pdf
en_US
dc.language.iso
en
en_US
dc.publisher
Copernicus
en_US
dc.rights.uri
http://creativecommons.org/licenses/by/4.0/
dc.title
A temperature- and stress-controlled failure criterion for ice-filled permafrost rock joints
en_US
dc.type
Journal Article
dc.rights.license
Creative Commons Attribution 4.0 International
dc.date.published
2018-10-17
ethz.journal.title
The Cryosphere
ethz.journal.volume
12
en_US
ethz.journal.issue
10
en_US
ethz.pages.start
3333
en_US
ethz.pages.end
3353
en_US
ethz.version.deposit
publishedVersion
en_US
ethz.identifier.wos
ethz.identifier.scopus
ethz.publication.place
Göttingen
en_US
ethz.publication.status
published
en_US
ethz.leitzahl
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02140 - Dep. Inf.technologie und Elektrotechnik / Dep. of Inform.Technol. Electrical Eng.::02640 - Inst. f. Technische Informatik und Komm. / Computer Eng. and Networks Lab.::03429 - Thiele, Lothar / Thiele, Lothar
ethz.leitzahl.certified
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02140 - Dep. Inf.technologie und Elektrotechnik / Dep. of Inform.Technol. Electrical Eng.::02640 - Inst. f. Technische Informatik und Komm. / Computer Eng. and Networks Lab.::03429 - Thiele, Lothar / Thiele, Lothar
ethz.date.deposited
2018-11-09T05:04:27Z
ethz.source
WOS
ethz.eth
yes
en_US
ethz.availability
Open access
en_US
ethz.rosetta.installDate
2018-11-28T08:09:23Z
ethz.rosetta.lastUpdated
2019-02-03T11:49:14Z
ethz.rosetta.versionExported
true
ethz.COinS
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