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International audience; The damage model presented in this article (named 'THHMD' model) is dedicated to non-isothermal unsaturated porous media. It is formulated by means of three independent strain state variables, which are the thermodynamic conjugates of net stress, suction and thermal stress. The damage variable is a second-order tensor. Stress/strain relationships are derived from Helmholtz free energy, which is assumed to be the sum of damaged elastic potentials and 'crack-closure energies'. Damage is assumed to grow with tensile strains due to net stress, with pore shrinkage due to suction and with thermal dilatation. Specific conductivities are introduced to account for the effects of cracking on the intensification and on the orientation of liquid water and vapor flows. These conductivities depend on damage and internal length parameters. The mechanical aspects of the THHMD model are validated by comparing the results of a triaxial compression test with experimental measurements found in the literature. Parametric studies of damage are performed on three different heating problems related to nuclear waste disposals. Several types of loading and boundary conditions are investigated. The thermal damage potential is thoroughly studied. The THHMD model is expected to be a useful tool in the assessment of the Excavation Damaged Zone, especially in the vicinity of nuclear waste repositories

International audience; This paper aims at obtaining a 3D fundamental solution for unsaturated soils under dynamic loadings in Laplace transform domain using the method of Hörmander. These solutions can be used, afterwards, in a convolution quadrature method (CQM)-based boundary element formulations in order to model the wave propagation phenomena in such media in time domain.

International audience; The site effects generated by topographical features are among the sources of amplifications and de-amplifications of the seismic signals, which can be important over large frequency domains. Site response analysis of topographical structures could only be solved accurately, economically and under realistic conditions, with the aid of numerical methods such as the Boundary Element Method (BEM). The BEM is a very effective numerical tool for dynamic analysis of linear elastic bounded and unbounded media. The method is very attractive for wave propagation problems, because the discretization is done only on the boundary, yielding smaller meshes and systems of equations. Another advantage is that this method represents efficiently the outgoing waves through infinite domains, which is very useful when dealing with scattered waves by topographical structures. This paper aims at obtaining an advanced formulation of the time-domain Boundary Element Method (BEM) for two-dimensional dynamic analysis of unsaturated soil. Unlike the usual time-domain BEM the present formulation applies a Convolution Quadrature developed by Lubich (1988) which requires only the Laplace-domain instead of the time-domain fundamental solutions. In this paper first of all, the set of fully coupled governing differential equations of a porous medium saturated by two compressible fluids (water and air) subjected to dynamic loadings is obtained. These phenomenal formulations are presented based on the experimental observations and with respect to the poromechanics theory within the framework of the suction-based mathematical model presented by Gatmiri (1997) and Gatmiri et al. (1998). In this model, the effect of deformations on the suction distribution in the soil skeleton and the inverse effect are included in the formulation via a suction-dependent formulation of state surfaces of void ratio and degree of saturation. In this formulation, the solid skeleton displacements , water pressure and air pressure are presumed to be independent variables. Secondly, the Boundary Integral Equation (BIE) is developed directly from those equations via the use of the weighted residuals method for the first time in a way that permits an easy discretization and implementation in a numerical code. The associated fundamental solution obtained by Maghoul et al. (2009) is used in the BIE. Then, once the BIE is derived, the focus shifts to an overview of the general purpose numerical implementation. Finally, the resulting BEM time domain formulation represents the first of its kind for two-dimensional dynamic problems in unsaturated soils.

International audience; This paper aims at obtaining an advanced formulation of the time-domain Boundary Element Method (BEM) for two-dimensional consolidation analysis of unsaturated soil. Unlike the usual time-domain BEM the present formulation applies a Convolution Quadrature developed by Lubich [1,2] which requires only the Laplace-domain instead of the time-domain fundamental solutions.

International audience; It has long been recognized that surface topographies can have crucial influences on damage severity and its spatial distribution during strong earthquakes. Site response analysis of topographical structures could only be solved accurately, economically and under realistic conditions, with the aid of numerical methods such as the Boundary Element Method (BEM). The basic idea of BEM consists of transformation of partial differential equation into a boundary integral equation and obtaining the fundamental solutions of the corresponding adjoint partial differential equations. Then a system of algebraic equations can be formed by bringing the field point to the surface, discretizing of surface and integrating numerically over it. In this paper, three-dimensional fundamental kernels for the integral equations or fundamental solutions of point force and source are obtained in frequency domain, for the dynamic unsaturated poroelasticity governing differential equations which are established in terms of solid displacements, water and air pressure.

International audience; In this paper, the boundary integral equations are presented for the set of fully coupled governing differential equations of hydro-mechanical behaviour of unsaturated porous media subjected to dynamic loadings in frequency domain. These boundary integral equations are derived via the use of weighted residuals method for the first time in a way that permits an easy discretization and implementation in a Boundary Element code. The formulation is accomplished using the solid skeleton displacement, water pressure and gas pressure as independent variables.