Assessing the sensitivity of steep rock slope permafrost to water infiltration under various fracture geometries: a numerical approach

• Main Authors: Bock, Josué, Magnin, Florence, Josnin, Jean-Yves, Ben-Asher, Matan
• Other Authors: Environnements, Dynamiques et Territoires de Montagne (EDYTEM), Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (Fédération OSUG), ANR-19-CE01-0018,WISPER,Processus thermo-mécaniques liés à l'eau et à la glace dans les fractures des parois alpines à permafrost(2019)
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2022
• Subjects: [SDE]Environmental Sciences; Ice; permafrost
• Online Access: https://hal.science/hal-04032881; https://hal.science/hal-04032881v1/document; https://hal.science/hal-04032881v1/file/Bock_Poster_IMC.pdf

International audience 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.