## 5 Conclusions and Recommendations for Further Research  
This study focuses on analyzing the differential effects and intrinsic mechanisms brought about by different pile body equivalent calculation methods in pile-anchor foundation pits' numerical simulation. The investigation is conducted from the perspectives of soil displacement and stress, stress paths at special points, and plastic zones. The main findings are as follows.  
1. With the increase in excavation depth, the displacement results produced by different pile equivalent calculation methods are significantly different, and the pile simulated with solid units has smaller horizontal displacement on the pile side and surface settlement. The displacement distribution characteristics under the simulation conditions of a one-dimensional structural unit and two-dimensional plate unit are basically the same, and the displacements are larger. In this study, the results of the solid unit with an interface unit are closer to the measured data.
2. The linear relationship between the maximum surface settlement and the maximum horizontal displacement of the pile side corresponding to the four simulation methods at each excavation stage can be characterized by the following equation: \(y=0.704x-1.902\) (\(R^{2}=0.98\)). Its pile-side displacement/excavation depth (\(\delta_{hm}/H\)) is clustered around 0.2% and its surface settlement/excavation depth (\(\delta_{vm}/H\)) is clustered around 0.15%.
3. As the excavation proceeds, the soil units close to the pile side move from the \(K_{0}\) line to the damage line, the \(K_{f}\) line, which is attributed to the effect of horizontal unloading caused by the foundation pit's excavation. In solid unit simulation conditions, the stress results show that stress concentration will be formed at a certain part of the pile side, which leads to a significant change in the stress paths near the pile side.
4. Among the four simulation methods, the solid unit with interface unit simulation method results in the lowest percentage of shear yield and tensile yield in the foundation soil, which may be attributed to the combination of the interface unit and the solid unit.  
Overall, the results of different pile body equivalent calculation approaches are significantly different. This study provides valuable insights into the equivalent calculation methods for pile bodies in numerical simulations. Of course, there are still some limita  
Figure 15: Normal and tangential stresses of the interface element at the 5 th excavation stage for Mode 2: (**a**) normal stresses of the interface element; (**b**) tangential stresses of the interface element.  
tions in the research work. These four simulation equivalent calculation methods should be applied to more engineering cases in the future and compared with the relevant site monitoring data to determine which model is suitable for specific engineering construction conditions.  
Conceptualization, X.L.; methodology, X.L. and H.L.; software, X.L. and H.L.; data curation, X.L. and D.W.; writing--original draft preparation, X.L.; writing--review and editing, C.W. and D.W.; project administration, C.W.; funding acquisition, C.W. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Natural Science Foundation of China (Grant No. 41972267).  
Not applicable.  
Data Availability Statement: Data may be requested from the corresponding author.  
The authors declare no conflict of interest.