Poster: Reducing the uncertainty of discrete fracture network models by ground penetrating radar imagery: case study at the Äspö Hard Rock Laboratory, Sweden

Event: ENIGMA Summer School, June 2018
Poster by Justine Molron, Niklas Linde, Ludovic Baron, Caroline Darcel, Philippe Davy, Jan-Olof Selroos


Predicting the flow and mechanical behaviour of fractured rock masses is a major challenge for a large number of hydrological and geotechnical applications. This is mostly achieved by deriving DFN models from field and core mapping and pumping tests. The present research project is focused on the conditioning of DFN models to geophysical imaging data close to tunnel walls. The objective is to develop a new approach for better assessing the safety of the bedrock barrier around canisters for nuclear waste disposal. We firstly investigate the possibility to use the Ground Penetrating Radar (GPR) geophysical method to identify fractures close to tunnel walls at depth. Secondly, the geophysical data shall be introduced in a broader DFN modelling framework which already involves structuralfractureand hydrological data.

The first GPR campaign was completed at the SKB Äspö tunnel Hard Rock Laboratory (HRL) in Sweden. The tunnel is roughly20 m long and 4 m width and height. Data interpretation is currently ongoing. Several significant fractures can be already identified. This information will be used to design a second experiment involving GPR measurements during pumping and tracer tests.

All the data acquired during the project will be made open sourceto contribute to improving our understandingofflow and transport patterns in fractured media. The methodology will offer a new approach for SKB to assess confinement properties of the bedrock barrier around canisters for nuclear waste disposal.


More about ESR4 research project