# Influence of Monolith Length on Temperature Field of Concrete Gravity Dams
## 4 Analysis Results
### Temperature Field during Construction  
The increase in the temperature due to hydration heat can be seen in Figures 18 and 19 (for the construction period), as well as in Figure 20 (for the period immediately after the completion of construction) for all the analyzed monolith lengths. These parts of the structure were recognized as zones with concrete temperatures in the range of 35.2-41.4 \({}^{\circ}\)C.  
The influence of winter air temperatures on the near-surface zones of the monoliths is evident in Figure 18, as well as in Figure 20 for all the analyzed monolith lengths. In Figure 19, which shows the temperature field at the time of the summer break from concreting, which lasted 135 days--from June 20 th to November 2 nd of the second  
Figure 19: Isometric view of the TF for different monolith lengths (283 rd day—27 July of the 2 nd year). Figure 20: Isometric view of the TF for different monolith lengths (512 th day—13 March of the 3 rd year). Figure 18: Isometric view of the TF for different monolith lengths (84 th day—10 January of the 2 nd year). year--the influence of the summer temperatures on the surfaces in contact with the air can be seen. Such extreme conditions, in combination with an increase in the temperature due to hydration, caused increases in the temperature of the cross-sections of the monoliths of the considered lengths (up to 41.0 \({}^{\circ}\)C). The influence of high air temperatures during the summer break was also reflected in the temperature field at the time of the completion of the monolith's construction (Figure 20). It can be seen that the concrete temperatures in the central cross-section area still significantly increased. It is emphasized that summer breaks during concreting as well as the proper curing of concrete during breaks (the use of covers, wetting the concrete) are extremely important in order to prevent excessive heating of the structure [35; 36; 37]. The concrete-curing process during the summer break was not considered in this research. In Figure 20, it can be seen that the cooling process can also be influenced by the galleries in the dam's body. As stated in [31], this boundary condition is set around the perimeter of all galleries. Therefore, its influence on the temperature field should be taken with reservations due to a lack of complete measurements, which is why the stated values were determined based on the mean monthly ambient temperatures. Figures 21-23 show the TF in selected horizontal cross-sections during construction for all the considered monolith lengths: at 146.50 m ASL for the 84 th day, at 169.0 m ASL for the 283 rd day, and at 162.75 m ASL for the 512 th day. The position of these horizontal cross-sections was chosen so that they represent the zones with increased values of concrete temperatures, as well as changes in these temperatures with monolith length variations. Additionally, the positions of the transverse and longitudinal sections (upstream-downstream and towards the river banks, respectively) of the horizontal planes are marked with dashed black lines, in which temperature changes with monolith length variations are shown. Figures 24-26 show diagrams of the concrete temperatures in a horizontal cross-section at 146.50 m ASL for the considered monolith lengths for the 84 th day from the beginning of construction. Based on the diagram, it can be concluded that the displayed temperatures decreased with a reduction in the monolith length, by a maximum of 0.4 \({}^{\circ}\)C when changing the monolith length from 20.0 m to 15.0 m, 1.1 \({}^{\circ}\)C when changing the monolith length from 20.0 m to 12.5 m, and 2.3 \({}^{\circ}\)C when changing the monolith length from 20.0 m to 10.0 m. The specified extreme values of the changes were not located at the points of maximum temperature values in the considered cross-section. Figure 21: The TF in the horizontal plane for different monolith lengths (84 th day—10 January of the 2 nd year—at 146.50 m ASL).