Geowissenschaften


Tara Wanninger (-Huber)
Experimental investigations for the modelling of anhydritic swelling claystones

Swelling Rocks, Swelling Processes, Anhydritic Claystones, Anhydrite Dissolution, Gypsum Precipitation, Self-Sealing

Anhydritic claystones are highly problematic for underground construction because of their swelling ability: When the rock comes into contact with water, the rock volume expands due to swelling of both clay as well as anhydrite. When the expansion is restricted, e.g., by an invert arch in tunneling, the swelling rocks can exert high pressures on the lining and damage the structure. The swelling behavior of purely argillaceous rock (containing solely swelling clays and no anhydrite) can be attributed mainly to osmotic processes and is well understood for the conceptual design of tunnels, as opposed to the swelling of anhydrite, where considerable knowledge gaps exist.

Florence Mezger
On the variability of squeezing behaviour in tunnelling

Tunnelling, Squeezing, Schistosity, Heterogeneity, Analytical Solution, Numerical Modelling, Segmental Lining

The magnitude of squeezing deformations in tunnelling often varies over short distances, even if there is no obvious change in the construction method, in the depth of cover, in the lithology or rock structure. As long as the reasons for the variability are not known, the tunnelling-induced convergences cannot be predicted with sufficient reliability. Reliable predictions, however, are important for determining the temporary support or the excavation diameter. Otherwise, large-scale tunnel repairs may be necessary, which can cause delay and additional costs due to remedial actions as well as due to the enforced interruption of other operations in progress at the same time.

Alexandru Marin
Dynamic non-linear soil behaviour in alpine areas

Silty Sand, Dynamic Behaviour, Earthquake Engineering, Basin Effects, Soil Structure Interaction, Alpine Valleys, Seismic Monitoring, Dams

Seismic events in alpine areas have a high impact on society. According to the U.S. Geological Survey, 9’182 casualties were caused by the two major earthquakes on April 24th and May 12th 2015 in Nepal, a country with predominantly rough topography.
Jean Nicolas François-Xavier Gautray
Influence of smear and compaction zones on the performance of stone columns in lacustrine clay

Gravel Columns, Bearing Capacity, Soil Conditions, Soil Characteristics, Lacustrine Clay

Construction on soft soils is always accompanied by the risk of significant, time-dependent settlement and bearing capacity failure. As technical knowledge has advanced, optimised ground improvement has offered significant economic advantages in reducing net settlement and resisting failure by installation of more flexible and cost-effective stone columns or sand compaction piles in the ground, rather than more rigid inclusions such as steel or concrete piles. The stiffness and strength of the subsoil around the columns is greater, and the consolidation time is reduced through shorter (radial) drainage paths.
Roberto Schuerch
On the delayed failure of geotechnical structures in low permeability ground

Tunnelling, Tunnel Jacking, Ground Stability, MC Model, MCC Model

This thesis investigates the problem of time-dependent stability of geotechnical structures (such as trenches or tunnels) in medium- to low-permeability water-bearing grounds, typically clayey or silty soils. The peculiarity of these soils is that they respond to excavation with a delay. The time-dependency can be traced back to the swelling process triggered by the dissipation of the excavation-induced negative excess pore pressures. Unstable conditionsmay necessitate improvement or reinforcement of the ground or the application of a support (e.g. by compressed air or pressurized bentonite slurry in the case of tunnel face). As such measures may present economical and operational disadvantages, the question of whether and for how long the excavation can remain stable without support is of great practical relevance. The stand-up time (time lapsing between end of the excavation and the occurrence of failure), and thus the feasibility of refraining from ground reinforcement, improvement or support, depends essentially on soil strength and permeability.

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Ulrike Kastrup | Bettina Gutbrodt | Gillian Grün | Andrea Dähler | Martine Vernooij | Iris Thurnherr..
BodenSchätzeWerte

Rohstoffnutzung, Rohstoffabbau, Mineralien, Erze, Steine und Erden, Metalle, Industriemineralien, Seltene Erden, Salze, Kies, Kohle, Erdgas, Bergbau, Ökotoxikologie

Kupfer für Stromkabel, Erdöl zum Heizen, Silber für Schmuck und Zink im Auto – mineralische Rohstoffe sind in unserem Alltag allgegenwärtig. Schon früh haben die Menschen mineralische Rohstoffe genutzt. Kenntnisse über Vorkommen und Anwendungsmöglichkeiten haben von jeher einen Vorteil bedeutet und oft Reichtum und Macht gefördert. Und auch heute sind Rohstoffe für viele Länder ein wichtiger Wirtschaftsfaktor. Die Verfügbarkeit von Rohstoffen ist für uns selbstverständlich und der weltweite Verbrauch nimmt stetig zu. Was sind die Folgen unserer zunehmenden Nutzung dieser nicht erneuerbaren Ressourcen? Welche Herausforderungen kommen auf uns zu?

Weijie Dong
On the role of constitutive behaviour in the response of squeezing ground to tunnelling

Rock Pressure, Tunnel, Tunnelling, Gotthard, Gibraltar Tunnel

The present thesis mainly addresses the influence of constitutive modelling on predictions about the response of squeezing ground to tunnelling in order to provide some general guidelines for basic engineering analysis. This objective is achieved by investigating the behaviour of squeezing rocks theoretically and experimentally, using samples from several tunnel projects, including the Gotthard base tunnel and the planned Gibraltar strait tunnel.
Sara Zingg
Static effects and aspects of feasibility and design of drainages in tunnelling

Advance Drainage, Drainage Boreholes, Tunnel, Face Stability, Limit Equilibrium, Fault Zone, Drainage Capacity, Equivalent Hydraulic Conductivity, Borehole Casing, Lead-Time, Groundwater Drawdown, Settlement, Inflow, Grouting Body, Displacement, Characteristic Line

This PhD thesis investigates the effectiveness of drainage measures with respect to two particularly important problems associated with tunnelling through water-bearing, weak ground: the stability of the tunnel face and the stability and deformation of grouting bodies. Water is an adverse factor with respect to the stability and deformation of underground structures due to the pore water pressure and the seepage forces associated with seepage flow towards the tunnel. Drainage boreholes reduce the pore water pressure and the seepage forces in the vicinity of the cavity. Furthermore, loss of pore water pressure increases the effective stresses and thus the shearing resistance of the ground ("consolidation"), which is favourable in terms the deformation occurring during and after tunnelling.
Saskia Willemse | Markus Furger (Hrsg.)
From weather observations to atmospheric and climate sciences in Switzerland

Weather Research, Meteorology, Atmospheric Sciences

In 2016 the Swiss Society for Meteorology (Schweizerische Gesellschaft für Meteorologie, SGM) celebrates its 100th anniversary. The idea of this book is to give an overview of what has happened in the field of atmospheric sciences in Switzerland since the first systematic long-term meteorological observations until today.

Anne Eckhardt | Klaus Peter Rippe
Risiko und Ungewissheit bei der Entsorgung hochradioaktiver Abfälle

Endlager, Entsorgungslösung, Resilienz, Sicherheitsrisiko, Atommüll

Die Entsorgung hochradioaktiver Abfälle ist ein anspruchsvolles Vorhaben. Wird dauerhafte Sicherheit für Menschen und Umwelt angestrebt, müssen die Abfälle nach heutiger Auffassung über einen Zeitraum von einer Million Jahren oder länger von der Biosphäre abgeschlossen werden. Ist es möglich, ein solches Ziel zu erreichen?

Amin Askarinejad
Failure mechanisms in unsaturated silty sand slopes triggered by rainfall

Landslide, Mudslide, Soil Mechnics, Hydraulic, Rhine, Rüdlingen

Landslides triggered by rainfall cause significant damage to infrastructure annually and affect many lives in several parts of the world, including Switzerland. These landslides are initiated by a decrease in the effective stresses, and hence the shear strength of the soil, as a result of the increase in pore water pressure.

Wilmer Ferney Morales Peñuela
River dyke failure modeling under transient water conditions

Flood Protection, Rhone, Failure Mechanism, Overflow

Knowledge of the performance of river dykes during flooding is necessary when designing governmental assistance plans aimed to reduce both casualties and material damage. This is especially relevant when floods have increased in their frequency during the last decades, together with the resulting material damage and life costs.

Emma Jane Pooley
Centrifuge modelling of ground improvement for double porosity clay

Braunkohlebergbau, Altlasten, Tonboden, Bodenverbesserung

Double porosity soil is characterised by a soil continuum containing two distinct porosities. Typically, this consists of macro-grains (lumps) of soil that have an internal porosity defined as the intragranular porosity. The spaces between lumps are identified as intergranular voids that give rise to the intergranular porosity.

Yuko Yamamoto
Instabilities in alpine permafrost: strenght and stiffness in a warming regime

Permafrost, Rock Glacier, Crawling Motion, Slope Instability, Geotechnical Engineering

Alpine permafrost exists at high altitude at lower latitudes, such as in the Swiss Alps. Accelerating climate change, including rising mean annual air temperature and extreme rainfall conditions in alpine regions induces permafrost degradation.

Pierre André Mayor
Verhalten eines Flussdammes unter wiederholter Hochwasserbelastung

Hochwasserschutz, Wasserretention, Rhone, Geotechnik

Die Hochwasserereignisse der letzten Jahrzehnte haben die Grenzen des Hochwasserschutzes deutlich ans Licht gebracht. Die Analyse der Auswirkungen von Klimaänderungen lässt zudem eine Erhöhung des Hochwasserrisikos befürchten. Viele Flussdämme als wichtiger Bestandteil des Hochwasserschutzes stammen aus dem 19. Jahrhundert und entsprechen nicht mehr dem heutigen Stand der Technik. Der Handlungsbedarf ist gross und es müssen Prioritäten entsprechend dem Gefährdungspotenzial gesetzt werden. In dieser Hinsicht sind zusätzliche Kenntnisse vom Verhalten der Flussdämme unter wiederholter Hochwasserbelastung und wechselnder Witterung notwendig.

Stefan Hirschberg | Stefan Wiemer | Peter Burgherr (Hrsg.)
Energy from the Earth

Geothermics, Energy Supply, Electricity Generation

Switzerland's Energy Strategy 2050 requires energy efficiency to be substantially improved, the proportion of fossil fuels in the energy supply to be considerably reduced, and nuclear power to be phased out, while meeting highly ambitious climate protection targets. One of the core implications is the need for a massive increase of the use of renewable sources for electricity generation.

Konstantinos Serafeimidis
On the dissolution, precipitation and transport processes in sulphatic swelling rocks

Tunnelling, Claystones, Gypsum Keuper, Swelling Process

Sulphatic claystones are among the most problematic rocks in tunnelling due to their distinctive swelling properties. They are known to have caused severe damage, for example, to numerous tunnels excavated in the Gypsum Keuper formation. The repairs were extremely costly and time-consuming, and often provided only a temporary solution. The setbacks experienced in tunnelling through Gypsum Keuper may be attributed, among other things, to our limited knowledge of the macroscopic principles governing the swelling process and the underlying microscopic mechanisms.

Gilles Rudaz | Bernard Debarbieux
Die schweizerischen Berggebiete in der Politik

Schweiz, Berggebietspolitik, Alpendiskurs, Berggebietsentwicklung, Alpenkonvention, Alpentransversale

Die Berge sind seit über 150 Jahren ein bedeutendes Thema in der Schweizer Politiklandschaft. Seit Mitte des 19. Jahrhunderts prägen sie massgeblich das Nationalbewusstsein, stellen eine wichtige touristische Ressource dar und waren insbesondere seit den 1920er-Jahren viele Male Gegenstand der öffentlichen Politik sowie unzähliger Kontroversen.

Wilfried Haeberli | Michael Bütler | Christian Huggel | Hansruedi Müller | Anton Schleiss (Hrsg.)
Neue Seen als Folge des Gletscherschwundes im Hochgebirge / Formation de nouveaux lacs suite au recul des glaciers en haute montagne

Gletscherschmelze, Gletschersee, Wassernutzung

Neue Seen als Folge des Gletscherschwundes im Hochgebirge: Klimaabhängige Bildung und Herausforderungen für eine nachhaltige Nutzung (Projekt NELAK des NFP 61).

Huib Ernste
Angewandte Statistik in Geografie und Umweltwissenschaften

Diese Einführung bietet einen Überblick über die häufigsten statistischen Methoden in den Fächern Geografie und Umweltwissenschaften. Sie bietet einen intuitiven Zugang und setzt nur wenig mathematische Kenntnisse voraus. Zugleich vermeidet sie kochbuchartige Anweisungen und vermittelt echte Einsicht in die Zusammenhänge. Mathematische Prinzipien werden erläutert und anhand von Beispielen und grafischen Darstellungen illustriert.

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