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

2016

E3S Web Conf.

Abstract. This paper presents an elastoplastic damage model for constitutive modelling of semi-brittle geomaterials showing two irreversible mechanisms. On one hand, the model deals with the plastic behaviour of a porous medium by a new variant of Barcelona Basic Model. On the other hand, the model combines the micromechanical definition of damage and phenomenological concepts in the framework of Continuum Damage Mechanics (CDM) for damage modelling. A second order tensorial damage variable is adopted for the model. Damaged effective stress variables are employed for formulation of elastoplastic behaviour laws and the plastic yield surface is a damage dependent one. The model has been validated by comparing the numerical results with experimental results of argillites.

“…Nonlinear elastic, elastoplastic and elasto-damage constitutive laws as well as soilatmosphere interaction model have already been incorporated in the code [21][22][23][24][25].…”

Section: Formulation Of Plastic Behaviourmentioning

confidence: 99%

Plasto-damage modelling for semi-brittle geomaterials

Alizadeh

2016

E3S Web Conf.

“…This induces a loss of effective surface in the material. 17,19 The effective stress is the stress that would develop in the intact material endowed of this reduced surface. In the following, the effective stress state variables are renamed damage stress state variables in order to avoid confusions with the concept of Biot's effective stress.…”

Section: Micromechanical Approachmentioning

confidence: 99%

“…4 and 5). 19 The basis of Pintado experiment is investigating the Thermohydroulic behavior of bentonite which is used as clay barrier in radioactive waste repositories. The boundary condition of this test is for the case that the waste is placed in galleries and the repository is closed and thus there is no ventilation or escape of moisture.…”

Section: Thermal Loading Test On Unsaturated Bentonitementioning

confidence: 99%

Coupled Analysis of Damage in Multiphase Media

Fathalikhani

J. Multiscale Modelling

2012

In this paper, the theoretical framework of a coupled thermo-hydro-mechanical damage model dedicated to non-isothermal unsaturated porous media is presented. The damage variable is a second-order tensor, and the model has been formulated in independent state variables. The approach combines thermodynamic and micromechanical theories. The behavior laws have been derived from a postulated expression of Helmholtz free energy. The damaged rigidities have been computed by applying the Principle of Equivalent Elastic Energy (PEEE). Internal length parameters have been introduced in the expressions of liquid water conductivity, to account for cracking effects on fluid flows. Damage has been assumed to have an isotropic influence on air and heat flows, through the inelastic component of volumetric strains. The damage model has been implemented in θ-Stock Finite Element program. Some numerical studies are conducted to the impact of the thermal and mechanical loading on the evaluation of response of the unsaturated bentonite, and investigation of model parameters effect on damage development.

“…The model has been implemented in Θ-STOCK Code which is a finite element code for analysis of coupled problems of multiphase porous media. The program is developed by Gatmiri and his co-workers and validated by various research and practical problems of geotechnical engineering (Alizadeh and Gatmiri, 2015a&b;Arson and Gatmiri, 2012;Arson and Gatmiri, 2011;Gatmiri et al, 2010a;Gatmiri and Arson, 2008;.…”

mentioning

confidence: 99%

An elasto-plastic damage model for argillaceous geomaterials

Alizadeh

2017

Applied Clay Science

Self Cite

The aim of this paper is to present a new elastoplastic damage model for unsaturated porous media. The proposed model within the context of poromechanics is intended for constitutive modelling of geomaterials which show two (irreversible) dissipative aspects involving plastic flow and damage. Independent stress state variables, namely net stress and suction, are adopted as stress variables of the model. Barcelona Basic Model is extended to a nonisothermal formulation and is coupled to a damage formulation using damage dependent yield surface and damaged stress variables. The stress state variables are transformed into the damaged state through the definition of effective damaged suction and effective damaged net stress in the framework of Continuum Damage Mechanics (CDM). Damage effects on intrinsic permeability and transfer laws are also taken into consideration. The model has been implemented in Θ-STOCK Code and predictive capabilities of the model have been evaluated against experimental results from the literature. The model is validated by comparing the numerical results with experimental results of argillites and results of an elastodamage model. The proposed model is also shown to give satisfactory simulation results which match the experimental data from a heating test on bentonite samples.