Thermo-hydro-mechanical modelling of an in situ heating experiment

In the context of a feasibility study for geological disposal of nuclear waste, an in situ heating experiment was performed in order to study the thermo-hydro-mechanical responses of a geological barrier to variation of temperature. The experiment was carried out at the Mont Terri underground research laboratory in Switzerland. This paper presents the numerical modelling of the experiment. An elasto-plastic damage model has been used to describe the mechanical behaviour of the geological formation (a mudstone). The constitutive model is extended to the description of the thermo-poro-mechanical behaviour of saturated porous media. A finite element method with fully coupled algorithm has been employed for the numerical solution of boundary value problems. Variations of temperature, pore pressure and deformation during heating phases have been evaluated and compared with in situ measurements. The numerical modelling allows the interpretation of coupled phenomena observed in the experiment.

[1]  J. Mazars.  APPLICATION DE LA MECANIQUE DE L'ENDOMMAGEMENT AU COMPORTEMENT NON LINEAIRE ET A LA RUPTURE DU BETON DE STRUCTURE , 1984 .

[2]  Paul Bossart,et al.  Geological and hydraulic characterisation of the excavation disturbed zone in the Opalinus Clay of the Mont Terri Rock Laboratory , 2002 .

[3]  M. Biot.  THEORY OF ELASTICITY AND CONSOLIDATION FOR A POROUS ANISOTROPIC SOLID , 1955 .

[4]  Maurice A. Biot,et al.  Nonlinear and semilinear rheology of porous solids , 1973 .

[5]  K. Willam,et al.  Triaxial failure criterion for concrete and its generalization , 1995 .

[6]  L. Dormieux,et al.  On the validity of the effective stress concept for assessing the strength of saturated porous materials: A homogenization approach , 1996 .

[7]  Jian-Fu Shao,et al.  Elastoplastic damage modelling of argillite in partially saturated condition and application , 2007 .

[8]  Jian-Fu Shao,et al.  Modeling of elastoplastic damage behavior of a claystone , 2003 .

[9]  Chun-liang Zhang,et al.  Experimental study of the hydro-mechanical behaviour of the Callovo-Oxfordian argillite , 2004 .

[10]  J. Shao,et al.  Stress equivalence principle for saturated porous media , 2002 .

[11]  Kunio Hayakawa,et al.  Thermodynamical Modeling of Elastic-Plastic Damage and Experimental Validation of Damage Potential , 1997 .

[12]  P. Berest,et al.  Creep behavior of Bure clayey rock , 2004 .

[13]  J. Ju,et al.  On energy-based coupled elastoplastic damage theories: Constitutive modeling and computational aspects , 1989 .

[14]  Sandra Escoffier.  Caractérisation expérimentale du comportement hydromécanique des argilites de Meuse/Haute-Marne , 2002 .

[15]  Zenon Mróz,et al.  A continuum model for plastic-brittle behaviour of rock and concrete , 1979 .

[16]  Luc Dormieux,et al.  Micromechanics of saturated and unsaturated porous media , 2002 .

[17]  Jian-Fu Shao,et al.  A coupled elastoplastic damage model for semi-brittle materials and extension to unsaturated conditions , 2006 .