Characterization of hydraulic nearfield phenomena in crystalline rock (Grimsel Rock Laboratory/GTS)

In co-operation with Nagra the GSF is carrying out investigations in the Grimsel Rock Laboratory/GTS in order to determine the spatial extension of an evaporation zone in the near field of an underground tunnel and to measure its influence on the water inflow from the surrounding granitic rock-mass. By the in situ ventilation tests (GSF/Nagra) and re-saturation measurements (Nagra) the water flow into the drift was determined as well as the extension of the saturated zone under varying ventilation conditions. It was expected that the ventilation causes an unsaturated zone, which will change the hydraulic regime, on a larger scale and will affect the water inflow into the drift