![Hier klicken, um den Treffer aus der Auswahl zu entfernen](images/unchecked.gif) |
Titel |
A 3-years full-scale mechanical ice deformation test from the artificial drainages of the Tête Rousse cavity |
VerfasserIn |
Olivier Gagliardini, Jean Krug, Fabien Gillet-Chaulet, Gael Durand, Adrien Gilbert, Emmanuel Thibert, Christian Vincent, Jérôme Weiss |
Konferenz |
EGU General Assembly 2013
|
Medientyp |
Artikel
|
Sprache |
Englisch
|
Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 15 (2013) |
Datensatznummer |
250077090
|
|
|
|
Zusammenfassung |
History of the city of Saint Gervais Mont Blanc, in the french Alps, is deeply marked by the
1892 disaster which killed 175 persons, after the unexpected release of 100000Â m3 of water
contained in a hidden cavity inside the Tête-Rousse glacier. During summer 2010, a
pressurised water-filled cavity of at least 50000Â m3 was again discovered within the glacier.
To avoid a repetition of the 1892 disaster, an unprecedented initiative has been risen up to
drain the water cavity under this high altitude glacier. This procedure was further repeated in
Autumns 2011 and 2012 since the cavity was permanently refiled in-between two drainages.
However, as the cavity was decreasing in size due to the creep of ice when the water
level was low, the total water volume drained out of the cavity was decreased each
Autumn.
At the same time, a dense network of stakes was deployed to survey the glacier surface
displacements above the cavity during the pumping. Record of the water level evolution
within the cavity together with the surface displacement measurements along an
almost 3-years period constitute a very well documented full-scale experiment to
characterise ice deformation. When the water level is low, the cavity is shrinking, whereas
when the cavity is full of pressurised water, the cavity is growing. Because of the
density ratio between ice and water, closing is approximately 9 time faster than
opening.
This dataset is completed by recently acquired surface and bedrock DEMs, as well as an
image of the cavity geometry from sonar and radar measurements. This unique dataset was
then used to constraint the finite-element ice flow model Elmer/Ice and perform transient
simulations over the 3-years period. Both the evolution of the surface displacements
and of the cavity volume are compared to measurements. We show the importance
of accounting for ice damage to reproduce the observed surface displacements. |
|
|
|
|
|