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  • Publication
    Métadonnées seulement
    Long-term simulations of thermal and hydraulic characteristics in a mountain massif: The Mont Blanc case study, French and Italian Alps
    (1999)
    Marechal, Jean-Christophe
    ;
    ;
    The use of hydrothermal simulation models to improve the prediction of water inflows in underground works during drilling is tested in the Mont Blanc tunnel, French and Italian Alps. The negative thermal anomaly that was observed during the drilling of this tunnel in 1960 is reproduced by long-term, transient hydrothermal simulations. Sensitivity analysis shows the great inertia of thermal phenomena at the massif scale. At the time of tunnel drilling, the massif had not reached thermal equilibrium. Therefore, a set of simulation scenarios, beginning at the end of the last glacial period, was designed to explain the anomaly encountered in the tunnel in 1960. The continuous cooling of alpine massifs due to infiltration of waters from the surface has occurred for 12,000 years and is expected to continue for about 100,000 years. Comparisons of water-discharge rates simulated in the tunnel with those observed indicate that this hydrothermal method is a useful tool for predicting water inflows in underground works.
  • Publication
    Métadonnées seulement
    Generation of granular media
    (1997) ; ;
    Parriaux, Aurèle
    A discrete reduced distance method to generate 2-D and 3-D granular porous media is presented. The main property of the method is to produce heterogeneous and/or anisotropic packed beds of joined grains with arbitrary shapes and optimum fitting (i.e., minimum porosity). The iterative generation process starts with the coarsest grain and adjusts the size and location of the next ones depending on the updated available space. Hence, grain size distribution cannot be specified directly but is merely the consequence of user defined input parameters. The latter consists of a set of randomly distributed initial points, a few typical predefined grain shapes as well as the minimum and maximum grain diameters. The simulated granular media can readily be processed by an appropriate mesh generator to allow for subsequent numerical solutions of differential equations.