Assessing the sensitivity of steep rock slope permafrost to water infiltration under various fracture geometries: a numerical approach
Résumé
Water infiltration and circulation in frozen bedrock fractures may enhance heat transport from the surface to the permafrost body and play a role in rock slope failure. However, such processes occurring in steep rock slope permafrost are difficult to investigate because of their non-linearity and anisotropy. In this communication, we will present recent developments conducted in the frame of the WISPER project (“Water and Ice related thermo-mechanical processes in the fractures of Steep alpine bedrock Permafrost”, funded by the French National Agency for Research). The FeFlow® (DHI-WASY) software is used to model and study the coupled heat and mass transfer in a simple alpine geometry that typically represents steep rock slope affected by permafrost and seasonal freeze and thaw cycles at c.a.3500 m a.s.l. Using a synthetic annual forcing for rock surface temperature, several case studies are implemented to investigate the sensitivity of permafrost degradation to various fracture networks features: width and density, orientation, angle, shape, amount and seasonality of the input water flux. The thermal and hydrogeological variables (notably temperature fields, and hydrostatic pressures), are compared to a base case without any fracture, in order to assess their sensitivity to the studied parameters. The comparison between these theoretical simulations and field measurements is considered through a number of diagnostic variables of the infiltrating water. The prospective framework to carry out field measurements and compare with the simulations will be presented.
Domaines
Sciences de l'environnementOrigine | Fichiers produits par l'(les) auteur(s) |
---|