## 3 Results and Discussion  
### Distribution of Vertical Earth Pressure  
Figure 4 shows the variation of the vertical dynamic earth pressure at each point in the GRSW with the gradually increasing loading. From the figure, it can be seen that, with the increase in loading times, the increase in the vertical dynamic earth pressure at the upper part of the GRSW on the right side of the DK315+913 section is relatively significant and then tends to be stable. This situation should be due to the lack of compactness caused by the original stable structure under the action of the excitation force being destroyed. When the soil particles are rearranged, the soil compactness increases further, and a stable structure is formed several times again. The lower part of the DK315+913 retaining wall has a higher compaction degree and a more substantial reinforcement material reinforcement effect. The compaction degree of the retaining wall reaches a higher degree, so it is difficult to destroy the original stable structure when it is subjected to vibration again. Hence, its vertical dynamic earth pressure has almost no change. Figure 3: Time–history curve of the measured vertical dynamic soil pressure. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Loading** & **Maximum Dynamic** & **Minimum Dynamic** & **Dynamic Stress** \\
**Frequency/Hz** & **Stress/kPa** & **Stress/kPa** & **Amplitude/kPa** \\ \hline
13 & 80.62 & 53.50 & 13.56 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Range of the dynamic load. Figure 2: Picture of the vibration test at the site. Figure 5 shows the distribution of the peak vertical dynamic earth pressure along the wall height of the GRSW at different load cycles in the longitudinal section where the earth pressure box T25-4 is located, calculated from the field-test monitoring data. It can be seen from the figure that the vertical earth pressure after loading is nonlinear along the wall height. Along the wall height, the decay trend from high to low is presented, the attenuation rate is lower and smaller, and the decay rate is 83.5%-86.9% in the wall height range of 2.7 m. The reason for the analysis was that there were gaps between the soil particles, and they were not sufficiently compacted. Under the action of its own gravity and external load, the pores in the upper part of the soil inside the retaining wall are reduced, the soil becomes dense, and the energy of the force is gradually consumed through the friction between the soil particles and other damping effects. As the soil becomes compact, the force energy is gradually consumed by damping effects such as friction between soil particles. At different heights of retaining walls, with the increase of load cycles, the vertical earth pressure also increases. The increase rate is the smallest at a depth of 2.7 m from the wall top, and the increase rate is the largest at a depth of 1.8 m from the wall top, which are 19.3% and 49.7%, respectively. Figure 6 shows the distribution of the peak vertical dynamic earth pressure along the length of the reinforcement at a wall height of 6.9 m for different numbers of load cycles. According to the figure, the vertical dynamic earth pressure varies nonlinearly along the length of the reinforcement and attends to increase and then decrease with the increase of  
Figure 4: Distribution of vertical dynamic soil pressure with increases in load cycle number. Figure 5: Distribution of vertical earth pressure along the wall height. the distance from the wall panel, and the peak value appears at the middle and rear of the reinforcement. As the number of load cycles increases, the vertical dynamic earth pressure near the wall panel is almost unaffected. This is due to the horizontal displacement of the wall surface, which reduces the vertical dynamic earth pressure near the wall surface by releasing it. The vertical earth pressure in the rear of the geogrid increases gradually and tends to be stable with the increase of load cycles.