## 3 Experimental Results
### Loading: Drying and Wetting  
Drying and wetting were applied in the top horizontal boundary, keeping constant the exterior temperature in this boundary and in the baseline and vertical equipment walls. The temperature applied in the soil surface and in the vertical walls of the cell was equal to the average temperature of the laboratory (T\({}^{0}\) = 24.4 \({}^{\circ}\)C). Temperature changes occur due to water vapor presence diffusing through the sample (perfect gas law). These changes, affected by a constant \(\gamma_{e}\), generate a flux of heat, given by Equation (16) [9]. \[j_{EI}=\gamma_{e}\Big{(}T^{0}-T\Big{)} \tag{16}\]  
The drying rate depends on the relative humidity of the room, while the wetting rate is controlled by the user in the definition of the time interval to which water in a liquid phase is added. Therefore, the drying rate is controlled uniquely by the equations solved by the program, while the wetting rate can be adjusted to achieve the target suction upon drying. Drying was simulated by applying water in the gas phase in the top horizontal boundary, creating a flow (\(j_{g}^{w}\)). The value prescribed, \(\rho_{w0}^{0}\) = (\(\rho_{g}\omega_{g}^{w}\))\({}^{0}\), was obtained from the relative humidity, RH, using Equations (11) and (12). The difference between this value and the \(\rho_{w0}\) computed with Equation (9), affected by a calibration constant \(\beta_{g}\), generates a water flow \(j_{g}^{w}\), given by Equation (17) [9]. \[j_{g}^{w}=\beta_{g}\bigg{[}\Big{(}\rho_{g}\omega_{g}^{w}\Big{)}^{0}-\Big{(} \rho_{g}\omega_{g}^{w}\Big{)}\bigg{]} \tag{17}\]  
It is important to highlight that a mean value of RH equal to 53% was recorded in the laboratory room during the test, but the sensor was placed around 1 m above the sample and the RH in the space close to the upper surface of the sample might be different from the recorded one. A value of RH equal to 65% was chosen in the first drying resulting from a previous sensitivity analysis performed to fit the maximum suctions measured at the tensiometers at the end of the first cycle. During the following infiltration (wetting), it seems realistic to assume a relative humidity equal to 100% in the volume of air surrounding the sample. Because the time interval between the cycles is not large enough for the RH equilibrium of all the air in the room, after the first wetting, it seems possible that the relative humidity in this environment close to the sample remains higher than the one in the room, creating a kind of a cloud. For this reason, values of RH equal to 75% have been chosen for the subsequent drying stages. This value was also found after fitting the results [15]. In the wetting phases, liquid pressure was also changed because suction decreases and becomes null if full saturation is reached (\(s\) = 0 MPa means \(P_{l}^{0}\) = 0.1 MPa). For this reason, the flow of water in the liquid phase was also prescribed, in which the pressure difference would generate water flow given by Equation (18), with consequent water transport by conduction (Equation (5)). For \(P_{l}\), a value slightly higher than that necessary to fully saturate the soil layer closer to the surface was prescribed to prevent instant evaporation [9]. \[j_{l}^{w}=(\omega_{l}^{w})^{0}\gamma_{l}\Big{(}P_{l}^{0}-P_{l}\Big{)} \tag{18}\]  
The values adopted for the different loads in the different surfaces are presented in Table 4. The time intervals in which each boundary condition was applied follow the experimental sequence. Constants \(\gamma_{l}\), \(\beta_{g}\) and \(\gamma_{e}\) were defined after a sensitivity analysis made by [PERSON] [15]. With these constants, it was possible to calibrate the model, with the purpose of being able to reach the target suction at the end of each drying cycle. Other attempts to simulate wetting and drying were performed, applied in all small changes in relative humidity for drying, and a small water head for wetting.