Rehabilitation of Urft Dam - Rock Mechanics Based on an Anisotropic Jointed Rock Model - page 782

Figure 24.14 Orientations of discontinuities (Wittke et al. 2012)
The results of the Lugeon tests carried out in the foundation rock revealed a large range
of scatter. However, in general, a decrease of permeability with increasing depth could
be observed. Figure 24.17 shows, for example, the k values determined in a vertical
borehole located in the middle of the valley. At a depth of approx. 13 m underneath
the foundation level, a considerable reduction of the rock mass permeability can be
seen, separating the weathered rock mass from the sound rock. Figure 24.18 shows, as
another example, the k values determined in an inclined borehole located at the right
abutment indicating a similar result. The results of all Lugeon tests yielded a thickness
of the weathered rock zone varying from 10 m to 15 m.