Rehabilitation of Urft Dam - Rock Mechanics Based on an Anisotropic Jointed Rock Model - page 776

Figure 24.6 Drilling KB 7 (Wittke et al. 2012)
Two LFJ tests were carried out in the upper inspection gallery in the masonry (Fig. 24.5).
Dilatometer tests and Lugeon tests were conducted in boreholes crossing both the ma-
sonry and the foundation rock.
24.4.2 Masonry Dam
Exploration and Testing
The drill cores indicated that the rubble stone masonry is in good condition (Fig. 24.6,
left). This impression was confirmed during excavation of the upper inspection gallery
(Fig. 24.7) where two LFJ tests (Section 15.4) were carried out in order to determine
deformability of the masonry. Both tests were carried out with three flat jacks, each
1.2 m wide and 1.5 m long, inserted in sawed slots (Fig. 24.8).
In test 1, the flat jacks were arranged horizontally in one sidewall of the upper in-
spection gallery. In test 2, the flat jacks were arranged vertically in the invert of the
gallery in the longitudinal direction, in order to check the masonry for anisotropic
deformability.
Several loading, unloading and reloading cycles were carried out, including phases of
constant load that may indicate time-dependent behavior. In Fig. 24.9, for example, the
stress-displacement curves measured in test 2 at deformeter 2/4 are represented. As a
result, the masonry to a large extent shows elastic behavior.