Rehabilitation of Urft Dam - Rock Mechanics Based on an Anisotropic Jointed Rock Model - page 794

In Fig. 24.29 the displacements measured by the pendulum (2.8 mm) and the inverted
pendulum (2.0 mm) due to a rise of the storage level of 20 m are shown separately, result-
ing in a total horizontal displacement of 4.8 mm (Fig. 24.28). Before the excavation of the
inspection galleries, the total horizontal displacement due to a rise of the storage level of
20 m amounted to ca. 8 mm (Fig. 24.28). Thus, the reduction of pore pressure acting on
the dam's base as a result of the excavation of the inspection galleries and the new drain-
age system led to a considerable decrease of horizontal displacements at the dam's crest.
Figure 24.30 shows the horizontal displacements of the crest due to a rise of the storage
level of 20 m, measured by the crown alignment. The displacements of 4 mm to 6 mm
measured at the middle of the dam were considerably larger than the displacements that
are measured near the slopes, indicating a pronounced arching effect.
Figure 24.29 Displacements due to change of storage level, monitoring and analysis (Wittke et al. 2012)