## 4 Analysis of Calculation Results
### Lateral Deformation of Retaining Structure  
Figure 9a shows the lateral deformation of the whole model, and Figure 9b shows the lateral deformation of the retaining structure. The lateral deformation of the whole model shows the characteristics of sliding mass failure, which is consistent with the deformation characteristics of deep foundation pit excavation. When excavating, the soil behind the retaining structure slides towards the inside of the foundation pit. Thus, the lateral deformation of the lower part of the retaining structure is larger than that of the upper part. The maximum lateral deformation of the retaining structure is close to the bottom of the foundation pit. The lateral deformation of the upper anchor cable is smaller than that of the lower anchor cable, indicating that the lower anchor cable bears more active soil pressure. The lateral deformation of the retaining structure shows that the maximum lateral deformation is 7 mm when excavating to the bottom of the foundation pit, meeting the requirements of construction control standards.  
From Figure 10a, the maximum settlement position of the retaining structure is at the pile top when excavating at small depth. With the increase in the excavation depth, the lateral deformation curve of the retaining structure becomes a parabolic curve, and the position of the turning point of the parabolic curve changes constantly. The position of maximum lateral deformation is about 0.9 times the excavation depth from the pile top. The anchorage depth of the pile is the main reason for the difference of the deformation curve when excavating shallow soil and deep soil. When excavating shallow soil, due to the long anchorage depth of the pile, the pile structure is similar to the cantilever structure, so the maximum deformation is located at the pile top. When excavating deep soil, the anchorage depth becomes short, the upper soil pressure is small and the soil pressure near the bottom of the foundation pit is large. Therefore, the soil lateral deformation near the bottom of  
Figure 9: Cloud atlas of lateral deformation. (**a**) Whole model., (**b**) Retaining structure.  
the foundation pit is large, while that at the pile top is small. When the excavation depth increases, the active soil pressure on the retaining structure also increases. During the initial excavation of the foundation pit, the horizontal displacement of the pile top is the largest, deforming as a cantilever structure, without the anchor cable. The displacement is small due to the shallow excavation depth. When the anchor cable is set, the horizontal displacement of the pile gradually increases and the position of the maximum deformation gradually moves downwards, with the inward convex deformation pattern.  
The maximum lateral deformation of the retaining structure by the PARB support system is reduced by 42%, which shows that the support effect of the PARB is better. The maximum lateral deformation of the retaining structure is consistent with the distribution of the maximum surface settlement. The maximum lateral deformation of the retaining structure increases rapidly when excavating shallow soil, but slows down when excavating deep soil.