Seite - 1093 - in Book of Full Papers - Symposium Hydro Engineering

Table 2 Piezometer measuring range from January 2015 to December 2017 Designation PZ8 (169m) PZ12 (138.86m) PZ14 (126.62m) PZJ1 (125.9m) Max (m H2O) 36 19 28 20 Min (m H2O) 13.2 0 1.9 2.7 (elevation of the measurement points is shown in curved brackets) 3. TRIGGER DEFINITION BASED ON THE OBSERVED BEHAVIOUR The definition of triggers for the uplift pressure measured through use of the piezometers is presented in this work. In order to show the proposed methodology, only the analysis of the uplift pressure measured in the PZ14 (126.6m) is presented. In the case of uplift pressures, the manual measurement was possible since September 2014 (time period more than two years) and the automated measurement was possible since July 2016 (time period less than one year). For these reason, manual measurements were used for the trigger definition. The data analysed corresponds to a period between January 2015 and December 2017, resulting more than 123 observations (manual measurements). The time evolution of the reservoir water level, air temperature and uplift pressure (manual and automated measurements) in the referred PZ14 (126.6m) are presented in Fig. 4. The readings were collected every two weeks for manual measurements and every hour for automated measurements. Among the different loads acting on concrete dams, it is usual to distinguish, as the most important ones for structures in normal operation, the hydrostatic pressure and the air temperature variation, Fig. 4. Fig. 4 Uplift pressure in the PZ14 (126.6m), reservoir water level and air temperature along time 1093