## 2 Materials and Methods--Measurement Site, Instruments, and Research Methodology  
Field studies of propagation of surface vibrations that are generated during the compaction of ground were conducted in the immediate vicinity of a newly built detached family house located at Ksiezyno near Bialystok, in Poland. This one-floor brick building with a habitable attic of the dimensions in a horizontal section 24.6 m \(\times\) 11.0 m and a height in a ridge of 8.9 m, was erected on a natural clay soil (sasiCI according to standard EN ISO 14668-1 [16] and EN ISO 14668-2 [17], plasticity index I\({}_{\text{p}}\) = 16%, liquidity index I\({}_{\text{L}}\) = 0.15). In the immediate vicinity of the building (up to a depth of approx. 1.8 m) there were mixed sand and clay soils, constituting an uncontrolled embankment. It was assumed that vibrations would be generated by using a new-generation hydraulic compactor type V8 from MTS integrated with an excavator, and a reversible plate compactor-type DPU 6055 from Wacker Neuson (operating frequency of 69 Hz, centrifugal force 60 kN) at three different locations spaced from the supporting wall of the building by 15 m (stage I), 10 m (stage II), and 5 m (stage III) and at three different depths of 1.8-2.0 m, 1.2 m, and 0.4 m. The compaction process was commenced with the excavation of a trench to a depth of about 2.3-2.4 m, and then the trench was partially filled up with sand and gravel mix, which was subsequently compacted. In this way, the depth of the trench decreased to approx. 1.8-2.0 m. After the completion of all planned series of measurements at a given depth, the trench was once more partially filled, and soil compaction continued on other analyzed depths. In the case of the MTS V8 hydraulic compactor, dynamic measurements were carried out for all three available modes of operation--i.e., X1 mode (so called \"Standard\")--with an operating frequency of 38 Hz and a centrifugal force of 90 kN, X2 mode (\"Compactor-jumper\")--at 45 Hz and 50 kN and X3 mode (\"Power\") of 60 Hz and 90 kN. Each time, before changing a device generating vibrations or changing the mode of operation, the ground at the desired depth was skimmed and loosened in order to provide comparable conditions of compaction. The research has been conducted at one measurement point located on the foundation wall of the residential building at the level of the surrounding terrain (measurement point No. 1--MP1) and at three measurement points located on the ground, at distances from the building: 2.5 m (MP2), 5.0 m (MP3), and 7.5 m (MP4)--in stages I and II, and consequently, at distances: 1.25 m (MP2B), 2.5 m (MP3B), and 3.75 m (MP4B)--in stage III. Measurements of vibration accelerations were carried out using 12-channel and 24-bit LAN-XI data acquisition hardware from Bruel&Kjaer, with analysis range exceeding 160 dB and dynamic signal range from 120 to 130 dB broadband and 160 dB narrowband, as well as with a set of three low-frequency, seismic piezoelectric accelerometers type 8340 manufactured by Bruel&Kjaer (measuring ranges: \(\pm\)0.5 g, 0.1-1000 Hz \(\pm\)5%) and nine low-frequency piezoelectric accelerometers type 3187D from Dytran (measuring ranges: \(\pm\)20 g, 0.48-1000 Hz \(\pm\)5%). In the course of measurements of the ground-borne vibrations, low-frequency uniaxial transducers type 3187D, were screwed to mounting devices (in a cubic shape) in three perpendicular directions: x, y, z, in measurement points MP2-MP4 (Figure 1) and MP2B-MP4B (Figure 2). Mounting devices were firmly attached to steel plates, placed on the ground surface, and secured in the ground by a three-point anchoring. A modal analyses carried out using a software based on the Finite Elements Method, showed that the natural frequency of mounting devices with accelerometers mounted to them was outside the frequency ranges relevant to the possible impact of vibrations on buildings.