## 3 Results  
From the SLT results, the curves between the settlement ratio and load (s/P), where s is the settlement and P is the applied load for all types of piles in the six testing zones, are presented in Figures 7-10. Thus, the tested piles in a protective shell, which are casted in a preliminary treated with sodium silicate solution soil, are presented in Figure 7. Here, pile #1 is a pile tested in zone 1, pile #2 in zone 2, and so on. Figure 6: Scheme of the anchor-stop stand for the static load test. 1—tested pile with protective and bearing shell; 2—main I-beam No.70; 3—secondary beams No.40; 4—anchor piles (steel pipes); 5—jack SMZh-158A (lifting capacity of 2000 kN); 6—6 PAO deflection indicator; 7—reference system; 8—manual pumping station HCP-40 with pressure gauge MTP-160. Figure 8: Correlation of loading P with settlement S according to the SLT results of the ordinary piles (without soil wetting). Figure 7: Curve of the correlation of loading P with settlement S according to the results of static tests of piles with a protective shell (without soil wetting). Figure 9: Correlation of loading P with settlement S according to the SLT results of the piles with a protective shell (with soil wetting). The values specified in the Standard p.p. 5.3-5.5 SP RK 5.01-103-2013 \"Pile foundations\" (2013) were taken as the criterion for the maximum permissible settlement. By the particular value of the limiting resistance of the pile to the compression load, Fu was understood as the load under which the reaction of the test pile takes a settlement equal to S, determined by the formula:  
\[S=\zeta S_{u,mt} \tag{2}\]  
where \(S_{u,mt}\) is the limiting value of the average settlement of the foundation of the designed structures, where industrial and civil one-storey and multi-storey buildings with a full frame is taken as equal to 8 cm (for reinforced concrete structures) according to the instructions of SP RK 5.01-103-2013 Pile foundations [33]. \(\zeta\) is the coefficient of transition from the limiting value of the average settlement of the foundation of structures \(S_{u,mt}\) to the settlement of the pile, obtained during static load tests with conditional stabilization (attenuation) of the settlement, taken as equal to 0.2 according to the instructions of SP RK 5.01-103-2013 \"Pile foundations\" [33]. The maximum permissible settlement is accepted to be 16 mm. The particular values of the experimental bearing capacities of the piles corresponding to the maximum permissible settlement are presented in Table 2.  
The results of the statistical check satisfy the condition \(|\text{Fn}-\text{Fi}|>\text{vS}\); therefore, all the obtained results of the carrying capacities can be considered valid and suitable for further analysis. Analysis of the influence of suffusion processes on the strength characteristics of soils was carried out for both types of pile loadings (Tables 3 and 4). A comparison was made between the bearing capacity of piles with the protective shell and the bearing capacity of ordinary piles after prolonged wetting. The functional linear dependence \(F^{\prime}_{u}\) to \(F_{u}\) is expressed by the \(k\) coefficient. \[k=\frac{F^{\prime}_{u}}{F_{u}} \tag{3}\]  
where \(F_{u}\) is the bearing capacity of piles according to the SLT without soil wetting, kN; and \(F^{\prime}_{u}\) is the bearing capacity of piles after prolonged wetting of soils, kN. Figure 10: Correlation of loading P with settlement S according to the SLT results of the ordinary piles (with soil wetting). The relationship between the bearing capacity of piles without and after wetting for piles with the protective shell and for ordinary pile is presented in Figures 10 and 11. Regression analysis of the functional dependence was performed using the least squares method. The bearing capacities were obtained from the coordinates of points on the plane,