**3. Results and Analysis**

In order to ensure the reliability of a building being erected it is necessary not only to choose a reliable foundation technology, but also to be able to predict the performance of the structure. With the help of Frost 3D simulation software, it is possible to obtain scientifically based predictions of the thermal regimes of permafrost soils in conditions of thermal influence of piles as well as of erected buildings and structures. This problem of heat distribution in the foundation over time in conditions of construction on permafrost soils is of primary importance.

According to the results of modeling for the year 2050, the following values and figures were obtained. Under the positive scenario with the temperature increase by 2.2 ◦C for the period from 2031 to 2050. (0.1 ◦C per year) the active layer will be 0.595 m. The modeling results of active layer changes due to warming up to 2050 under a positive scenario are shown in Figure 7.

**Figure 7.** Temperature distribution for 2050 under a positive warming scenario.

Under the neutral scenario with a temperature increase by 3 ◦C for the period from 2031 to 2050. (0.16 ◦C per year) the active layer will be 0.673 m. The modeling results of active layer changes due to warming up to 2050 under a neutral scenario are shown in Figure 8.

**Figure 8.** Temperature distribution for 2050 under a neutral warming scenario.

Under the negative scenario with an increase in temperature by 4.8 ◦C for the period from 2031 to 2050. (0.24 ◦C per year) the active layer will be 0.840 m. The modeling results of active layer changes due to warming up to 2050 under a negative scenario are shown in Figure 9.

**Figure 9.** Temperature distribution for the year 2050 under a negative scenario of warming.

Under the local negative scenario with temperature increase by 9.6 ◦C for the period from 2031 to 2050. (0.5 ◦C per year) the active layer will be 1.868 m. The modeling results of active layer changes due to warming up to 2050 under a local negative scenario are shown in Figure 10.

**Figure 10.** Temperature distribution for 2050 under a local negative warming scenario.

The simulation results (Table 3) showed that under a positive warming scenario (with an increase of temperature by 0.11 degrees per year), the active layer will be 0.595 m, the bearing capacity of the pile will be 81.93 tons in 2050. Under a neutral warming scenario (with an increase of temperature by 0.16 degrees per year), the active layer will be 0.673 m, and the bearing capacity of the pile will be 75.84 tons. In negative and locally negative scenarios, the active layer will be 0.840 and 1.868 m, respectively. The bearing capacity of the pile will be 71.32 and 63.79 tons. Analyzing the results, it can be concluded the active layer by 2050 may increase threefold, while the bearing capacity of the piles will decrease by more than 20%. In order to avoid emergency situations and to ensure further safe operation of construction facilities, it is necessary to provide additional measures.


**Table 3.** Results of modeling the bearing capacity of the soil for various scenarios.

Besides, there was carried out the ground temperature state modeling when using seasonally acting cooling devices. The distribution of ground temperature when using thermosiphons for the winter period of 2050 under the local negative scenario is shown in Figure 11.

The distribution of ground temperature when using thermosiphons for the summer period of 2050 under the local negative scenario is shown in Figure 12.

**Figure 12.** Modeling results of ground temperature distribution in the summer period.
