During the course of the GMT experiment numerous tests were performed to investigate the small-scale behaviour of the sand-bentonite backfill material (Fig. 1). In these experiments, methods were tested for the visualisation of flow-paths of water and gas, and new concepts developed to describe physically the phenomenology of water and gas transport and, in particular, to up-scale these parameters from the small laboratory scale to the large repository scale.

FORGE project at Grimsel : Columns used to visualise water flow-paths (a) and gas flow-paths (b) through sand/bentonite material

Figure 1: Columns used to visualise water flow-paths (a) and gas flow-paths (b) through sand/bentonite material

Laboratory Column Experiments (FORGE)