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Last name: CHEMENDA
First name: Alexandre
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The bifurcation analysis of compaction banding is extended to the formation of a tabular discrete compaction-band array. This analysis, taken together with the results of finite-difference simulations, shows that the bifurcation results in the formation of intermittent loading (elastic–plastic) and unloading (elastic) bands. The obtained...
Abstract The origin of open‐mode fractures or joints, common in sedimentary basins (reservoirs), remains incompletely understood. These fractures require effective tensile stress for their formation, yet they usually develop at depths where effective compressive stresses dominate. Through 2‐D finite‐difference elastoplastic modeling, we...
The overwhelming majority of experimental tests on rocks have only been conducted for a single value of the Lode angle θ corresponding to the axisymmetric compression (AC). There are now sufficiently extensive data sets from both AC and axisymmetric extension (AE) tests (corresponding to two extreme θ values) for two materials, synthetic rock...
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Networks of localized compactive and isovolumetric shear bands were generated in 2-D finite-difference models. They reproduce the most striking feature of the evolution of natural deformation bands characterized by compactive (or non-dilatant) inelastic volumetric deformation, i.e., the band thickening from the flanks by incorporation of the...
It is known that rock fracture includes inelastic straining or damage that should localize at a certain loading stage and result in fracture initiation. The details of this process are not clear, and it is frequently omitted in the models by imposing the initial microcracks (seeds) with certain lengths and orientations. Here we investigate 2-D...
Compactive shear bands with different ratio of compactive to shear inelastic deformation were recently studied in detail in different regions within the porous rocks. Among them are nicely exposed networks of conjugate cataclastic bands formed in a single tectonic event in the "Bassin du Sud-Est" (Provence, France) in Cretaceous sandstones....
An accurate analysis of fracture and cleavage anisotropies along two landslides in the Argentera massif (French Southern Alps) was performed in order to relate the fracturing mode to the rock slope failure state. The mature La Clapière landslide and the incipient Isola Landslide were investigated. In both cases, the gneissic rock schistosity...
Our field study examines two sites revealing the processes responsible for fault surface development and fault rock juxtaposition along normal faults in porous-sandstone–dominated formations. At the first site, we show that a cluster of cataclastic deformation bands made in an initially poorly consolidated sandstone localizes overprinting of a...
Fracturing (jointing) affects large volumes of rocks and strongly impacts their mechanical stability and permeability. In layered sedimentary basins, the fractures typically form subparallel sets with different fracture spacing S. This parameter has been extensively studied both in the field and in mechanical models in relation to the thickness...
Natural discontinuities (eg, joints, faults, and bedding planes) are generated through long-term geological processes. The mechanical response of rock mass is known to be greatly impacted by these discontinuities. The existence of these discontinuities has been the principal obstacle to estimate precisely the deformability and stability of rock...
The majority of experimental rock fatigue tests have been conducted with the continuous cyclic loading path. In this paper we report the results from the fatigue tests of salt with discontinues cyclic loading path containing zero loading stress intervals (ZLIs) of different duration. We show that the application of such intervals strongly...
The Paleozoic French Variscan Belt in Massif Central and Massif Armoricain is a collision belt that provides a good example of a suture zone where ophiolites are rare, and the frontal (i.e., the magmatic arc) part of the upper plate is not present. In the lower plate (or Gondwana), the continental rocks are subdivided into an Upper Gneiss Unit...
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Fracture process is investigated using finite-difference simulations with a new constitutive model. It is shown that both geometry and fracture mechanism itself depend on the preexisting heterogeneities that are stress concentrators. In the brittle regime (low pressure, P), Mode-I fractures propagate normal to the least stress σ3 from the...
We investigate the deformation localization at brittle-ductile transition in axisymmetric compression tests of rock analogue material GRAM1 made of bonded rigid particles. This transition in rocks (as well as in GRAM1) is recognized by the formation of a network of conjugate deformation localization bands in the postmortem rock samples and by a...
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