Study of desaturation and resaturation in brittle rock with anisotropic damage

In the THM modeling of multiphase medium, the coupling effects of skeleton, suction, and temperature have been integrated via the concept of state surfaces of void ratio and degree of saturation. Based on proposed formulation, a fully coupled numerical model for the behavior of soil deformation, water flow, air flow, heat flow in unsaturated soil has been developed and integrated in a finite element code θ-Stock by the first author. This program is conceived with this idea that it will be able to analyze the response of a soil in different states of humidity to mechanical, thermal loading, and also damage phenomena. Damage model is dedicated to unsaturated brittle rocks. It mixes phenomenological and micromechanical concepts and is formulated based on the use of independent state variables. The expression of the liquid permeability is modified in order to represent the influence of fracturing on interstitial fluid flows. The final matrix form of established field equations of the proposed model for unsaturated case has been encoded for this particular purpose, in a finite element program which had been developed for dry and saturated soils previously.

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“…Comparison of matric suction change results of present study 32 and the results of simulation done by Indraratna et al30 …”

mentioning

confidence: 54%

“…This is not the choice that has been done by the authors, but such an approach has been adopted by Shao research team. 25,30 Adapting this approach to the framework of mechanical and capillary strains, such a postulate writes:…”

Section: Extending Damage Models To Unsaturated Materialsmentioning

confidence: 99%

A MULTIPHASE ANALYSIS FOR ENVIRONMENTAL IMPACT ASSESSMENT WITH Θ-Stock FINITE ELEMENT PROGRAM

Gatmiri

Hemmati

Arson³

et al. 2010

J. Multiscale Modelling

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“…Most of the damage models proposed for rocks account for mechanical damage only, even for saturated and unsaturated media (Shao et al, 2005). However, temperature changes can have a dramatic effect on inelastic strains and cracking.…”

Section: Thermo-mechanical Constitutive Equationsmentioning

confidence: 99%

Thermo-Mechanical Damage in Porous Rocks: Theoretical Framework and Modeling Considerations

Arson

2012

GeoCongress 2012

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This work focuses on the concurrent effects of stress and temperature changes on the opening and closure of cracks in porous rocks. A phenomenological approach is used to express the damaged tangent properties of rock. The model couples an anisotropic mechanical damage model initially designed for solids to an isotropic thermal damage model developed for salt rock. The solid mechanics damage model is improved according to the poro-mechanical thermodynamic framework. Deformation is decomposed into purely elastic, mechanically damaged, and thermally damaged strains. Thermal damage is defined so as to account both for crack opening and crack closure. Preliminary numerical results illustrate the importance of thermo-mechanical couplings on cracking. This research work is expected to bring new insights in thermo-hydromechanical damage modeling in unsaturated rocks, for possible applications on nuclear waste management.

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“…Argillaceous rocks are intensively studied as possible host rocks for underground radioactive nuclear waste disposal in the last decades. During different stages of the service life, such rocks are subjected to some humidification/desiccation processes that may lead to damage phenomena . These damage phenomena modify the permeability of the host rock and are unfavourable for the sealing of a long‐term repository .…”

Section: Introductionmentioning

confidence: 99%

Modelling the internal stress field in argillaceous rocks under humidification/desiccation

Wang

Pouya

Bornert

et al. 2014

Num Anal Meth Geomechanics

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International audienceThis paper deals with analytical and numerical modelling of the internal stress generated in argillaceous rocks during humidification/desiccation processes, which is an essential issue for damage study. This local stress field arises from two mechanisms: (i) complex interactions between free swelling/shrinking clay matrix and non-strained inclusions of carbonate and quartz and (ii) a self-restraint effect induced by the moisture gradient during the transient moisture exchange process. The inclusion-matrix interaction is investigated in different cases. Firstly, the analytical solution of the stress around a cylindrical inclusion embedded in an infinite swelling matrix is derived: The inclusion would suffer tension (compression) under humidification (desiccation), and the resulting cracking patterns are discussed. Then, the problem of two inclusions with different distances in an infinite swelling matrix is considered, and it is shown that the local stress around an inclusion will be perturbed and amplified by neighbouring inclusions. Finally, an inclusion outcropping at the free surface of a swelling matrix is modelled as to investigate the effect of free surface: The inclusion-matrix interface undergoes shear stresses of which the maximum is found at the free surface. In addition to the inclusion-matrix interaction, the self-restraint effect is investigated: The induced stress is maximal at the beginning of humidification/desiccation processes and vanishes gradually with time. The quantity of the self-restraint stress is strongly controlled by the hydric loading rate

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Study of desaturation and resaturation in brittle rock with anisotropic damage

Cited by 27 publications

References 21 publications

A MULTIPHASE ANALYSIS FOR ENVIRONMENTAL IMPACT ASSESSMENT WITH Θ-Stock FINITE ELEMENT PROGRAM

A MULTIPHASE ANALYSIS FOR ENVIRONMENTAL IMPACT ASSESSMENT WITH Θ-Stock FINITE ELEMENT PROGRAM

Thermo-Mechanical Damage in Porous Rocks: Theoretical Framework and Modeling Considerations

Modelling the internal stress field in argillaceous rocks under humidification/desiccation

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