Project

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Long-term damage evolution in brittle rocks subject to controlled climatic conditions

English title Long-term damage evolution in brittle rocks subject to controlled climatic conditions
Applicant Löw Simon
Number 170746
Funding scheme R'EQUIP
Research institution Geologisches Institut ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Other disciplines of Earth Sciences
Start/End 01.12.2016 - 30.06.2019
Approved amount 165'000.00
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All Disciplines (2)

Discipline
Other disciplines of Earth Sciences
Civil Engineering

Keywords (9)

long-term creep testing; progressive damage evolution; uniaxial compression; environmental chamber; brittle rock; cyclic loading; static load control (>100 days); near-surface bedrock behavior

Lay Summary (German)

Lead
Die progressive Entwicklung von Rissen in Fels unter statischer oder zyklischer Belastung bestimmt die Entwicklung der Schädigung in Felshängen und um künstlich geschaffene Untertagebauten, wie einem Tunnel, über längere Zeit. Um die Reaktion von alpinen Felshängen oder Tunnels auf Unterschiede der mechanischen Belastung (z.B. Gletscherrückgang, Entlastung) oder des Klimas (z.B. Temperaturschwankungen, Wasserverfügbarkeit) vorherzusagen, ist es entscheidend, zuerst die Mechanismen dieser Schädigung in sprödem Gestein über längere Zeit verstehen.
Lay summary

Ziel dieses Forschungsprojektes:

Während mehrere Forscher signifikante Fortschritte in diesem Thema gemacht haben, sind die kombinierten Effekte von Temperatur, Feuchtigkeit und mechanischer Belastung auf die Geschwindigkeit des Risswachstums sowohl in der Felsmechanik als auch in der Bodenmechanik eine Herausforderung geblieben. Dies teilweise aufgrund eines Mangels an relevanten Labordaten und zum Teil aufgrund der Tatsache, dass wenig bis gar nicht auf dem Gebiet der direkten Verbindung zwischen zeitabhängigen Labordaten und Feldbeobachtungen geforscht wird. 

Wir beabsichtigen die Grenzen des Verständnisses des progressiven Risswachstums durch die Kombination von Labordaten, von neuen speziell angefertigten Kriech-Testmaschinen (imstande die Temperatur, Feuchtigkeit und mechanische Belastung über mindestens 100 Tage zu regulieren), mit Messungen von bereits existierenden Installationen im Feld zu erweitern. Erste Untersuchungen werden sich auf besondere natürliche und künstlich geschaffene Umgebungen/Objekte (Långöreninsel, Finnland, und Bedrettotunnel, Schweiz) konzentrieren, um die Einflussgrössen zu bestimmen. Im Labor beabsichtigen wir die Einflüsse der einzelnen Variablen auf das Risswachstum zu isolieren. Das Erarbeiten dieser Verknüpfung zwischen Labor- und Feldbeobachtungen ist ein wichtiger Schritt, um bessere Modelle zur Vorhersage zu entwickeln.

Wissenschaftlicher und gesellschaftlicher Kontext:

Das Verständnis und die Fähigkeit die Auswirkungen von Veränderungen der Umwelt auf die Geschwindigkeit des Risswachstums vorherzusagen ist wichtig für den Schutz von Gemeinden, die möglicherweise von Hanginstabilitäten betroffen sind, um die Integrität von existierender Infrastruktur untertage zu erhalten und um die Planung von Langzeit-Tiefenlagerung von Abfällen zu verbessern.

Direct link to Lay Summary Last update: 29.11.2016

Lay Summary (English)

Lead
The progressive development of fractures in rock subjected to static or cyclic loading determines the long-term damage evolution in rock slopes and around man-made underground excavations, such as tunnels. In order to predict the response of alpine rock slopes or underground tunnels to changes in mechanical loading (e.g. deglaciation, relaxation), or, in climate (e.g. temperature fluctuations or water availability), it is essential that we first understand the mechanics of long-term damage evolution in brittle rock.
Lay summary

Aims of the research project:

While a number of researchers have made significant progress on this topic, the combined effects of temperature, humidity, and mechanical loading on fracture growth rates remains a frontier in both rock mechanics and Earth surface process research. This is, in part, due to a lack of relevant laboratory data, and partly due to the fact that there is little to no research directly investigating a link between temporal laboratory data and field observations 

We aim to advance the frontier of progressive fracture development by combining laboratory data derived from new custom built creep testing machines (capable of regulating temperature, humidity, and mechanical load over at least 100 days) with measurements from existing field equipment. Initial testing will be focused on unique natural and man-made environments (Långören Island, Finland, and Bedretto Tunnel, Switzerland) to determine the influencing variables. In the laboratory we aim to isolate the impact of these individual variables on fracture growth. Developing the linkages between laboratory and field observations is an important first step in developing better predictive models.

Scientific and societal context:

Understanding and being able to better predict the impact of changes in the environment on the fracture growth rates is important for protecting communities that maybe affected from rock slope instabilities, for preserving the integrity of existing underground infrastructure, and for improving our designs of long-term underground waste isolation facilities. 

Direct link to Lay Summary Last update: 29.11.2016

Responsible applicant and co-applicants

Publications

Publication
A new laboratory to undertake climatically controlled static loading and constant strain tests: design and preliminary results
LiYing, A new laboratory to undertake climatically controlled static loading and constant strain tests: design and preliminary results, in Proceedings of ARMA Conference, New York CityAmerican Rock Mechanics Association, Washington, USA.

Collaboration

Group / person Country
Types of collaboration
Permafrost & Schneeklimatologie, WSL SLF Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Risk-group - ISTE - Institute of Earth Sciences - UNIL Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Micro and Nanosystems - CLA - ETHZ Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
- Industry/business/other use-inspired collaboration
Department of Earth and Environmental Sciences, University of Milano Bicocca Italy (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
CHYN - Université de Neuchâtel Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
ARMA Conference Poster Poster presentation 23.06.2019 New York City, United States of America Leith Kerry; Perras Matthew;


Associated projects

Number Title Start Funding scheme
146593 Paraglacial Rock Slope Mechanics (Phase II) 01.10.2013 Project funding
112073 Rockslide processes and mechanisms: Progressive development of shear/slide surfaces in rock slopes (Phase III) 01.07.2006 Project funding

Abstract

The progressive development of fractures in brittle rock subjected to static or cyclic loading determines the long-term evolution of landslide activity, erosional processes and of man-made underground excavations, such as tunnels, mines, and nuclear waste repositories. In order to predict the response of alpine rock slopes to changes in mechanical loading (e.g. through deglaciation), or, climate (e.g. increasing temperatures or water availability), and, the degradation of infrastructure as a result of ongoing mechanical stress changes, or, variations in temperature, available water, or water chemistry, it is therefore essential that we first understand the mechanics of long-term damage evolution in brittle rock.While a number of researchers have made significant progress developing theoretical models supported by laboratory observations, the combined effects of temperature, humidity, and mechanical loading on fracture rates (otherwise known as ‘static fatigue’, or ‘stress corrosion’) remains a frontier in both rock mechanics and Earth surface process research. This is, in part, due to a lack of relevant laboratory data, and partly due to the fact that there is little to no research directly investigating a link between temporal laboratory data and field observations. The Applicants aim to advance this frontier by combining laboratory data derived from new custom built creep testing machines (capable of regulating temperature, humidity, and mechanical load over at least 100 days) with measurements from existing field test sites. Initial testing will be focused on unique natural and man-made environments (Långören Island, Finland; Bedretto Tunnel, Switzerland; Preonzo rockslide, Switzerland), while pursuing a strategy to better understand the long-term behavior of Alpine rock slopes, aging infrastructure and new underground facilities relevant to Switzerland, and society in general. The requested funding will support the purchase of two custom static load machines with integrated climate chambers for control of temperature (-20 - 150° C) and humidity (10 - 95%) during testing. Maximum uniaxial loads of between 1000 and 2000 kN are required to allow testing of crystalline rocks in analogue near-surface settings, and the dual frame arrangement will allow long-term tests to be run in parallel, while a shared hydraulic pump and loading controls optimize cost. Coupled with microseismic sensors, these features set the proposed testing ma-chines apart from available facilities in Europe, and along with existing and planned field pro-jects will allow unparalleled insight into damage evolution in near-surface bedrock environments to help safeguard important infrastructure.
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