# Centrifuge Model Investigation of Interaction between Successively Constructed Foundation Pits
## 4 Conclusions  
Using centrifuge model tests, this study investigated the interaction between two adjacent foundation pits during the successive excavation. By analyzing centrifuge test results, the stress and deformation characteristics of two adjacent foundation pits, the earth pressure distribution of the middle adjacent retaining wall, the stress characteristics of the support, and the trends of ground settlement between adjacent foundation pits were described. The specific conclusions of this study are as follows:  
1. During the construction of foundation pit B, diaphragm wall No. 1 experienced a negative bending moment, the support experienced tension, and the wall top deformed toward the middle. Corresponding measures should be taken in real projects to avoid tension in support members.
2. The stress and deformation of the retaining wall as well as the axial force of the support of foundation pit B were markedly larger than those of foundation pit A. Therefore, for similar practical projects, a foundation pit with high protection requirements should be constructed later.
3. The active earth pressure of the middle soil of diaphragm wall No. 1 during the construction of foundation pit A was higher than that of diaphragm wall No. 2 during the construction of foundation pit B.
4. The settlement of the middle soil in the construction of foundation pit B was larger than that in the construction of foundation pit A, indicating that the settlement of the middle soil was superimposed during the construction of two adjacent foundation pits.
5. During the construction of two adjacent foundation pits, the displacement of wall 3 was greater than that of wall 2, indicating that during the construction of two adjacent foundation pits, foundation pit B was offset toward foundation pit A, but only slightly.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Axial Force of Strut** & **ZC-1** & **ZC-2** & **ZC-3** & **ZC-4** & **ZC-5** & **ZC-6** \\ \hline Step 1 & 654 & 1798 & & \(-\)198 & & \\ Step 2 & 476 & 3362 & & \(-\)211 & & \\ Step 3 & 144 & 2657 & 4212 & \(-\)225 & & \\ Step 4 & & & & 1130 & & \\ Step 5 & & & & 882 & 1382 & \\ Step 6 & & & & 826 & 1250 & 2760 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Supporting axial force of each construction step (kN).  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Construction Steps** & **Step 1** & **Step 2** & **Step 3** & **Step 4** & **Step 5** & **Step 6** \\ \hline Surface subsidence & & & & & & \\ (cm) & 9.6 & 10.4 & 10.9 & 5.3 & 6.6 & 6.9 \\ \hline \hline \end{tabular}
\end{table}
Table 5: Surface subsidence of each construction step.  
**Author Contributions:** Conceptualization, S.C. and F.L.; methodology, J.C.; software, S.C.; formal analysis, F.L.; investigation, J.C.; resources, S.C.; data curation, S.C.; writing--original draft preparation, J.C. and S.C.; writing--review and editing, F.L. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** The data are contained within the article.  
**Acknowledgments:** The authors wish to express their gratitude to the anonymous reviewers whose constructive comments helped improve the overall quality of the paper.  
**Conflicts of Interest:** The authors declare no conflict of interest.