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| Titel |
3D thrusting in frictional wedges : comparison between experimental observations and numerical predictions by limit analysis |
| VerfasserIn |
Pauline Souloumiac, Kristian Krabbenhoft, Bertrand Maillot, Yves M. Leroy |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250078598
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| Zusammenfassung |
| The objective is to capture 3D failure mechanisms, i.e., thrust surfaces in compressive
accretionary wedges by the sole knowledge of the material and interface strengths. A 3D
simple prototype composed by a flat sand layer topped with a wedge on one side and
maintained between two lateral rigid walls is shortened by the relative movement of the two
end walls. We consider laboratory data that demonstrate the important influence of the side
wall friction on the position of thrust faults and on spurious departures from plane
strain conditions, by comparing outcomes using the two possibles configurations of
sand boxes (fixed or mobile base) (Souloumiac et al., J. Struc. Geol., 2012). The
proposed method to reproduce these observations is the limit analysis. The 3D virtual
velocity field is constructed by spatial discretisation. The numerical tool based
on the limit analysis allows us to take into account the influence of the side wall
friction and to find the 3D failure modes observed in the laboratory at the onset of
thrusting. The comparison with the analogue experiments shows the connection
between the virtual 3D velocity field and the actual deformation, and validates the
numerical method. It is further applied to cases with lateral variations of surface
slopes and basal friction to illustrate respectively the lateral transition from super
to sub-critical conditions and the surface effect of patches of low friction on the
décollement. |
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