Julien Ambre - Academia.edu (original) (raw)
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Papers by Julien Ambre
Inelastic strain analysis of rock under stress is of first importance to build up adequate theory... more Inelastic strain analysis of rock under stress is of first importance to build up adequate theory of inelastic deformation and failure of geomaterials. The latter is crucial to have a better understanding of natural processes such as landsliding or seismic fault activity. In laboratory experiments, a rock sample can be easily stressed and different methods are used to study the deformation as for exemple X-ray tomography, or digital image correlation. But during the compression process of the sample, these technique don’t allow to access the 3-D strain tensor.
Comptes Rendus Mécanique, 2011
Extension fractures of two types defined by the mean stress σ were generated in a synthetic rock ... more Extension fractures of two types defined by the mean stress σ were generated in a synthetic rock analogue material. When σ is very small, the fractures are mode I cracks with smooth surfaces. At higher σ , these surfaces have plumose topography, with the amplitude increasing with σ . Both SEM observations and mechanical measurements show that fractures/discontinuities in the latter case are initiated as dilatancy localization bands. They form under tensile or slightly compressive normal stress and can be seen as running constitutive instabilities. The similarity between the plumose fractography of the experimental fractures and natural joints suggests similarity in the formation mechanism.
Journal of Geophysical Research, 2011
Inelastic strain analysis of rock under stress is of first importance to build up adequate theory... more Inelastic strain analysis of rock under stress is of first importance to build up adequate theory of inelastic deformation and failure of geomaterials. The latter is crucial to have a better understanding of natural processes such as landsliding or seismic fault activity. In laboratory experiments, a rock sample can be easily stressed and different methods are used to study the deformation as for exemple X-ray tomography, or digital image correlation. But during the compression process of the sample, these technique don’t allow to access the 3-D strain tensor.
Comptes Rendus Mécanique, 2011
Extension fractures of two types defined by the mean stress σ were generated in a synthetic rock ... more Extension fractures of two types defined by the mean stress σ were generated in a synthetic rock analogue material. When σ is very small, the fractures are mode I cracks with smooth surfaces. At higher σ , these surfaces have plumose topography, with the amplitude increasing with σ . Both SEM observations and mechanical measurements show that fractures/discontinuities in the latter case are initiated as dilatancy localization bands. They form under tensile or slightly compressive normal stress and can be seen as running constitutive instabilities. The similarity between the plumose fractography of the experimental fractures and natural joints suggests similarity in the formation mechanism.
Journal of Geophysical Research, 2011