# Research on Construction Sequencing and Deformation Control for Foundation Pit Groups
## 3 Results  
### Segmented Foundation Pit Behavior  
This part shows and analyzes the deformation results of diaphragm walls under various excavation sequences for the segmented foundation pit. The objective is to evaluate how excavation order--deep-to-shallow, shallow-to-deep, and synchronous--impacts the deformation behavior and displacement magnitudes of the retaining structures. The findings followed provide insights into selecting optimal excavation sequences to minimize wall displacement and ensure structural stability. For the first group with the deep-to-shallow construction sequence, the horizontal displacement curves of diaphragm walls 1# to 3# at each excavation stage, plotted against excavation depth, are shown in Figure 10. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Typical Soil** & **Common Types** & **Compression** & **Selection of Scaling** \\  & **Modulus** & \(\mathbf{E_{s}^{0.1-0.2}}:E_{ood}^{ref}\cdot E_{50}^{ref}:E_{w}^{ref}:E_{w}^{ ref}:E_{0}\) \\  & & & \(\mathbf{E_{u}^{ref}:E_{u}^{ref}:G_{0}}\) \\ \hline Soft Soil & soft clay, silty soil, etc. & 2–3 & 1:1:5:8:20 \\ \hline Clay & normally consolidated clay, silty clay, silt, etc. & 6–8 & 1:1:1:5:10 \\ \hline Sandy Soil & fine sand, medium sand, silty sand, sandy gravel, etc. & \textgreater{}18 & 1:1:1:3:5 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Empirical parameter methods for various moduli of typical soils. During the excavation of deep foundation pit A (Phases 1-3), lateral displacements of the retaining structure primarily occurred at the outer wall 1# and the shared wall 2#. The horizontal displacement increased progressively with excavation, with the maximum displacement at each step located above the excavation face. The final maximum displacements were 0.223 mm and 0.218 mm, respectively, both directed toward the interior of Pit A. During this phase, the shared wall 2# tilted toward the deep pit, and its displacement gradually increased, while the displacement of the outer wall 3# of the shallow pit was nearly zero. During the excavation of shallow foundation pit B (Phases 4-5), the displacement of the shared wall 2# shifted from negative to partially positive values, indicating that the upper part of the wall transitioned from tilting toward the deep pit to tilting toward the shallow pit. This was due to significant soil unloading after the shallow pit excavation, causing wall 2# to incline toward the shallow pit side. For the outer wall 1# of the deep pit, the maximum displacement slightly increased from 0.223 mm to 0.252 mm in Phase 4 but remained relatively stable during subsequent shallow pit excavation. The outer wall 3# of the shallow pit exhibited a \"concave\" deformation pattern, with a maximum displacement of 0.255 mm. For the second group with the shallow-to-deep construction sequence, the horizontal displacement curves of diaphragm walls 1# to 3# at each excavation stage, plotted against excavation depth, are shown in Figure 11.  
During the excavation phase of shallow foundation pit B, specifically Stages 1-2, the lateral displacement of the retaining structure primarily occurs at the exterior wall 3# and the shared wall 2# of the shallow foundation pit. As the excavation progresses, the horizontal displacement gradually increases. The maximum horizontal displacement at each excavation step is consistently observed above the excavation face. Both walls 2# and 3# tilt towards the excavation side of the shallow pit, and their maximum horizontal displacement at each excavation step, are shown in Figure 12.  
Figure 11: Horizontal displacement diagrams under the “shallow to deep” excavation sequence. Figure 10: Horizontal displacement diagrams under the “deep to shallow” excavation sequence. placements gradually increase to 0.228 mm and 0.351 mm, respectively. The displacement of the exterior wall 1# of the deep pit remains almost unchanged.