## 3 Test Results
### Lateral Displacement of Soil  
Before construction, the soil is in a static equilibrium state. After being squeezed by the pile, the soil is under passive pressure. After the construction is stopped, the soil is in an active state. Figure 5 depicts driven pile lateral soil displacement under different states. It can be seen that the shallow soil moved towards the pile on the machine setup. The first pile section led to a shallow soil backward shift, and the second section produced significant middle soil movement away from the pile. After the third section, the soil moved further, reaching 27 mm max. Deep displacement changed significantly at 40 m depth, around 10 mm. Soil started moving back towards the pile 8 h post-construction, and continued at 16 h, making at 10 mm after 24 h. The soil's peak lateral displacement appeared above the pile bottom plane (10-20 \(d\)). This trend relates to soil layer properties, resembling the \"saddle-shaped\" curve observed by [PERSON] et al. (2001) [9]. At A-CX1, the closer distance to the pile axis resulted in larger lateral soil displacement compared to A-CX2. The closer proximity to the pile axis led to greater radial soil displacement. A-CX2, further from the pile, experienced less overall compression than A-CX1 at the same depth. Figure 6 illustrates lateral soil displacement around PGP piles with depth. During drilling, pile-side soil moved toward the pile axis. After a 12-h drill pause, the soil partly rebounded. Upon reaching max depth and erecting a larger head, pile-side soil continued moving toward the pile, peaking at -7.5 mm around 1/3 \(L\). Drill withdrawal and grouting led the lower soil to shift toward the pile. After two pile sections, soil on the pile side  
Figure 5: Comparisons of soil lateral displacement of driven pile. (**a**) A-CX1; and (**b**) A-CX2. moved away from the body, with rapid changes around 30 m. After full implantation, max lateral displacement was about 10 mm, and there were notable bulges at 10 and 35 m. The soil gradually recovered post-construction, moving about 7.5 mm back to the initial displacement. For B-CX2, drilling shifted soil toward the pile. A 12-h pause showed less soil recovery on the pile side. Max depth and a larger head led the bottom pile-side soil to the pile. Max lateral displacement was \(-\)7.5 mm around 15 m depth. Drill withdrawal and grouting led to continued soil shift, \(-\)5.3 mm near the surface. Soil on the pile side moved away from the pile after two sections. Complete implantation had about 5 mm max lateral displacement. After construction, the soil rebounded to about \(-\)5 mm displacement. After the soil is extracted by drilling, the surrounding soil will move towards the pile under the influence of active earth pressure, and after the prefabricated pile is implanted, the passive earth pressure will make it move back to the pile. The driven pile does not have the step of drilling, so the soil will not move towards the pile actively during the construction process. Before and after construction, PGP piles' lateral soil displacement remains consistent. During construction, soil goes through three phases: toward, away, then back to the pile, aligning with the pile construction method. Soil near the piling hole loses stability during drilling, and moves due to lateral pressure. During pile installation, cemented soil filling and hole shrinkage cause soil extrusion, which is pushed aside by the pile. Pile-induced soil compression is minimal due to the hole. Post-construction, soil pore pressure dissipates, rebounding around the pile. The rebound is consistent across radial distances, making at 7.5 mm.