Powerhouse Cavern Estangento-Sallente - Rock Mechanics Based on an Anisotropic Jointed Rock Model - page 737

measurements. During the excavation of the vault, various convergence measure-
ment cross-sections were placed and further extensometers were installed in the vault
(Fig. 22.12, Section 17.5).
During the installation of the support of the vault consisting of a 25 cm thick reinforced
shotcrete membrane and a systematic grid of 5 m long rock bolts with a spacing of
1.5 m x 1.5 m (Fig. 16.23), pressure cells were installed in the shotcrete at different loca-
tions (Fig. 22.12, Section 17.6).
Figure 22.12 Monitoring program (Wittke 1990)
During the excavation of benches, further convergence measurement cross-sections
were installed. On the heads of a number of tendons, anchor load cells (see Section
17.7) were mounted to monitor changes of the pre-stressing forces with advancing ex-
cavation.