 |
| Titel |
3D stability of accretionary wedges by application of the maximum strength theorem |
| VerfasserIn |
P. Souloumiac, Y. M. Leroy, K. Krabbenhoft, B. Maillot |
| Konferenz |
EGU General Assembly 2009
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250023865
|
|
|
|
|
|
| Zusammenfassung |
| The objective is to capture the 3D failure modes in accretionary wedges and their analogue
experiments in the laboratory from the sole knowledge of the material and interface strengths.
The proposed methodology relies on the maximum strength theorem inherited from classical
limit analysis. The virtual velocity field is constructed by spatial discretization. The
numerical scheme is first applied to a perfectly-triangular 2D wedge. It is shown
that the 2D critical slope αc for stability is captured precisely by the numerical
scheme, the ramp and the back thrust corresponding to regions of localized virtual
strain. The influence of the back-wall friction on αc is explored, explained by the
Mohr construction and by analogue experiments with sand. The first 3D problem
concerns a wedge with a lateral variation in its topographic slope α so that it is
sub-critical (α < αc) and super-critical (α > αc) to the right and to the left boundary,
respectively. It is shown that the localized deformation of the ramp on the right side, is
getting diffuse as one moves to the left side where more décollement is activated.
The influence of the two lateral boundaries is felt for wedge widths even greater
than the length. The second 3D problem explores the influence of the side wall
friction on the results of laboratory experiments. It is found that the deformation is
diffuse close to the side wall with a vertical stretching and less dcollement activated.
The side wall influences the rest of the wedge over a width 1.5 times the wedge
thickness, for realistic friction angles. Comparison with analogue experiments shows
the connection between the virtual 3D velocity field and the actual deformation. |
|
|
|
|
|
|