## 5 Results and Discussions  
A comparison of the measured and calculated values for the calibrated set of filtration parameters is presented. The numerically calculated potential values (Mp) at the measuring points are compared with the measured potential values and numerical values of the nearest neighbor node (Nn) (Figure 13). It can be seen that there is a difference between the numerical values at the measuring point and the numerical value of the nearest node. The difference depends on the distance between the measurement point and the nearest FE model node. This difference increases as the size of the element containing the measurement point increases. Using the interpolation algorithm presented in this paper, the average relative difference for pore pressure is reduced from 8.89% to 8.10% for the data shown in Figure 13.  
For the observed measuring points and adopted calibrated values, the individual relative deviation of the calculated piezometric level from the measured piezometric level was found to be 10.9% on average, with a standard deviation of 10.4%. Deviations between the measured and calculated values may result from the division of the surrounding terrain into quasi-homogeneous zones. The existing approach applied to the FEM model for defining these zones has shown some shortcomings, such as lack of continuity in the spatial distribution of some material zones. These problems highlighted the need for updates to the current FEM model, particularly in terms of the arrangement and continuity of quasi-homogeneous zones in the field.  
The thermal finite element model of the dam was calibrated using available data obtained from thermometers. Transient thermal analysis for determining thermal distribution within the dam body at corresponding times and for corresponding reservoir water level and ambient temperature was performed. The measured temperatures and numerically calculated values at the measuring points in lamella ten are shown in Figures 14 and 15. The position of thermometers T60, T84, T87, and T90 is shown in Figure 4a. As can be seen for these figures, the measuring points T60 and T84 have better matching then measuring points T87 and T90.  
The proposed algorithm was used for calibrating the filtration coefficients and thermal characteristics of concrete. The input parameters (boundary condition) for calibration were the measured values of the upper and lower water levels, air temperature, water temperature, and temperatures in the galleries. Calibration was carried out by comparing the measured values in piezometers/thermometers (in the work, measuring points) with the calculated values for selected boundary conditions (e.g., the elevation of the upper and lower water levels for the filtration calculation). The differences between the actual and measured values for the calibrated parameters are shown in Figures 13-15.  
Figure 13: Measured potential vs. numerical potential values.  
the nodes of the 2D cross section in the 3D model. The modifications of the algorithm in Figure 6 areas follows: input parameters are 3D elements and nodes of 2D cross section; output is an ASCI file that contains the ID of the 2D node, the ID of the 3D element in which the node is located, the coordinates of the 2D element, and the local coordinates. Equation (8) is used to calculate the potential/temperature values in the nodes of the 2D cross section. Figure 16 shows the potential field through the axis of lamella 10. The potential field in the 2D cross section is shown in Figure 16a, and the potential field through the 3D model is shown in Figure 16b.