## 4 Discussion
### Comparative Analysis of the PPAs
Considerably lower values of ground surface vibration acceleration are generated by a plate compactor (with the exception of direction y in the second stage of the test (see Table 3), where at measurement points MP2 and MP3 reported values were significantly higher than in the case of the MTS V8 compactor). However, this is the direction in which there are much lower vibration acceleration levels, compared to the horizontal direction x and the vertical direction z. Regarding the effect of the depth of compaction on the level of recorded surface vibrations of the ground, it can generally be concluded that the closer to the source of the vibration, and the lower the depth of work with the use of the MTS V8 hydraulic compactor and the DPU 6055 vibratory plate compactor from Wacker Neuson--the higher the level of acceleration of surface vibrations recorded on the surface of the ground. Along with the increasing distance from the source of vibration, this tendency changes and the vibrations generated at greater depths and recorded on the ground are usually more intense. This is particularly evident if we compare the distribution of PPAx values recorded in the longitudinal direction x on the surface of the ground, listed in Table 2 (stage I--source of vibration at a distance of 15 m from the building and from 7.5 m to 12.5 m to the measurement points located on the ground) with the corresponding PPAx values in Table 4 and in Figure 4 (stage III--source of vibrations only 5 m from the front wall of the building and from 1.25 m to 3.75 m in the horizontal line to the measuring points on the ground). Thus, the maximum PPAx values presented in Figure 4 in the majority of cases related to the lowest compaction depth (0.4 m), while in Table 2, the predominant PPAx values corresponded to a depth of 1.2 m or 1.9 m.  
When it comes to the PPAi values recorded at the outer foundation wall of residential building at the first measurement point (MP1) in the most important direction from the point of view of the possible impact of vibration on building (in the x direction), it can be seen that in the case of vibrations generated at a distance of Ls = 15 m from the outer wall of building (stage I, see Table 2), the PPAx values generated by the operation of the hydraulic compactors type V8 from MTS (0.235 m/s2--X2 mode at a depth of h = 0.4 m) were twice as high than in the case of the operation of a vibrating plate compactor (0.111 m/s\({}^{2}\), h = 0.4 m). The same maximum level of vibration acceleration as in the standard plate compactor was obtained in the case of vibrations generated during the operation of the hydraulic compactor in X3 mode (0.111 m/s\({}^{2}\), h = 1.2 m). When the location of the compactors was closer to the building (stage II--Ls = 10 m, see Table 3), the highest levels of the PPAx values registered on the building were observed in the case of compactor MTS V8 operating in the mode X1 at a depth of 0.4 m (0.226 m/s\({}^{2}\)). The vibration accelerations generated by the vibratory plate compactor were, in this case, much more intense (0.195 m/s\({}^{2}\), h = 1.2 m) than in a case of hydraulic compactor operating in mode X3 (0.170 m/s\({}^{2}\), h = 1.2 m), and only slightly lower than in mode X2 (0.201 m/s\({}^{2}\) when h = 0.4 m). In stage III (Ls = 5 m, see Table 4 and Figure 4), with the smallest distance of sources of vibrations from the building (Ls = 5 m, see Table 4 and Figure 4) by far the highest PPAx values were recorded in the case of the MTS V8 device operating in X1 mode (0.790 m/s\({}^{2}\), at h = 0.4 m). Even by several dozen percentage points, lower vibration acceleration peaks were recorded during the operation of the MTS V8 compactor in X3 and X2 modes (respectively: 0.531 m/s\({}^{2}\) and 0.376 m/s\({}^{2}\)). The smallest PPAx values occurred during the operation of a vibratory plate compactor (0.225 m/s\({}^{2}\), h = 0.4 m). In stage III, the intensity of vibration accelerations recorded on the foundation wall of the building decreased each time with increasing compaction depth.