# Research on Construction Sequencing and Deformation Control for Foundation Pit Groups
## 5 Conclusions  
This paper conducted indoor physical model tests on two common types of foundation pit configurations in underground space engineering: segmented foundation pits and adjacent foundation pits. The deformation patterns of retaining structures under different construction sequences for adjacent foundation pits were obtained, and parameter analysis was performed using PLAXIS 3D (a three-dimensional finite element analysis software). The main conclusions are as follows:  
1. Based on the test results of segmented foundation pit excavation, the synchronous excavation sequence is beneficial for controlling the deformation of the shared diaphragm wall due to simultaneous unloading on both sides. In contrast, sequential excavation, especially the \"deep-to-shallow\" sequence, results in more complex soil stress paths and smaller deformations of the exterior walls. 2. The test results of adjacent foundation pit excavation show that the deformation of the diaphragm wall on the adjacent side is generally smaller than that on the far side. Synchronous excavation should be prioritized. Under sequential excavation, the overall deformation trend of the diaphragm wall first tilts toward the initially excavated pit and then toward the subsequently excavated pit, causing alternating positive and negative horizontal displacements, which adversely affect the diaphragm wall. The sequence of excavating the larger-section pit first and then the smaller-section pit generates relatively smaller additional displacements for the initially excavated main pit. 3. As the ratio of foundation pit spacing to excavation depth (B/He) increases, the active earth pressure curve approaches the at-rest earth pressure. The active earth pressure curve exhibits an inflection point near the excavation face, with a linear distribution trend below the inflection point. When the pit spacing is less than one times the excavation depth (B/He \(<\) 1), the horizontal displacement of the retaining structure is significantly influenced by the foundation pit spacing. When the foundation pit spacing exceeds one times the excavation depth (B/He \(>\) 1), the influence of foundation pit spacing on horizontal displacement diminishes. For future research, we recommend investigating the effects of different soil types and geological conditions on foundation pit deformation and stability. Additionally, expanding the research to more complex foundation pit configurations and developing more advanced numerical models to simulate foundation pit behavior under various construction scenarios would be valuable contributions to the field. Field experiments should also be conducted to further validate the findings from the model tests and numerical simulations presented in this study. Conceptualization, Z.Y., R.J., S.G. and Z.C. ; Methodology, Z.Y., R.J. and S.G.; Software, Z.Y. and R.J.; Validation, Z.Y., R.J. and Z.C. ; Formal analysis, Z.Y., R.J., S.G., Z.C. and G.D.; Investigation, Z.Y., R.J. and G.D.; Resources, Z.Y., R.J., S.G. and G.D.; Data curation, Z.Y. and S.G.; Writing--original draft preparation, Z.Y., R.J., S.G., Z.C. and G.D.; Writing--review and editing, Z.Y., R.J., S.G., Z.C., G.D. and W.Z. ; Visualization, Z.Y. and R.J.; Supervision, Z.Y., R.J., S.G., Z.C., G.D. and W.Z. ; Project administration, Z.Y. and S.G.; Funding acquisition, S.G., G.D. and W.Z. All authors have read and agreed to the published version of the manuscript. **Funding:** This research was funded by the National Natural Science Foundation of China (No. 52378328, 52208333), Research Fund for Advanced Ocean Institute of Southeast University (Key Program KP202404; General Program GP202403). **Institutional Review Board Statement:** Not applicable. **Informed Consent Statement:** Not applicable. **Data Availability Statement:** The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author(s).