Page - 822 - in Book of Full Papers - Symposium Hydro Engineering

2. FOUNDATION OF THE DAM Most of the Mavčiče Dam is founded on permeable Quaternary conglomerate bedrock, so that a cut-off grout curtain had to be constructed to a depth of up to 60 m below the ground surface, i.e. up to 296 - 302 m above sea level, where a layer of impermeable Oligocene marine clay occurs. The foundation of the machine hall is, for instance, at the altitude of 309.50 m. However, the erection bay, which is located on the right bank of the dam, is founded on a layer of gravel backfill, up to about 25 m thick, which lies on top of the conglomerate bedrock. The upper courtyard, which is located behind the erection bay, has an altitude of 348.00 m, whereas the lower courtyard, which lies in front of the erection bay, is located 10.75 m lower, i.e. at the altitude of 337.25 m [3]. The foundation of the right portion of the dam is presented in Fig. 3. Fig. 3 The foundation of the right portion of the Mavčiče Dam 3. MONITORING SYSTEM OF THE DAM Long-term manual technical monitoring of the behaviour of the dam began in 1986, at the time of the dam's completion, and included all necessary types of measurements and inspections. In 1999 to 2000 the supplemented monitoring system of the detailed behaviour of the right bank of the dam was established, which included twenty-six points for the vertical displacement measurements. Eighteen of these points (indicated by 1 to 10 and by A to H) were located in the upper courtyard, whereas the other eight points (indicated by 11 to 18) lies in the lower courtyard (see Fig. 4). 822