# Research on Construction Sequencing and Deformation Control for Foundation Pit Groups
## 3 Results
### Adjacent Foundation Pit Behavior  
The excavation and deformation behaviors of adjacent foundation pits differ significantly from segmented configurations due to their closer proximity and direct mutual influences. This section presents the deformation results from physical model tests conducted under three distinct excavation sequences: small-section first followed by large-section excavation, large-section first followed by small-section excavation, and synchronous excavation. By analyzing the variations in diaphragm wall displacement patterns across these scenarios, this study identifies optimal construction sequencing strategies to mitigate deformation and enhance the stability of retaining structures in adjacent foundation pit groups. Figure 12: Horizontal displacement diagrams of walls under synchronous excavation conditions. The first group followed the construction sequence of excavating the smaller section first, followed by the larger section. The horizontal displacement of diaphragm walls 1# to 4# at each excavation stage, plotted against excavation depth, is shown in Figure 13.  
From the figure, it can be observed that during the excavation of Pit A, the deformation of diaphragm wall 1# is slightly larger than that of diaphragm wall 2# due to the presence of diaphragm wall 3#. During the subsequent excavation of Pit B, the horizontal displacement of retaining wall 1# continues to increase gradually, while that of diaphragm wall 2# further decreases, as shown in Stages 4 and 5 of Figure 13b. The primary reason is that during the excavation of Pit B, the earth pressure acting on diaphragm wall 2# decreases, causing the entire foundation pit to tilt toward the subsequently excavated Pit B. For diaphragm wall 3#, during Stages 1-3, due to the unloading caused by the excavation of Pit A, the soil outside the pit tends to move toward Pit A. In Stages 4-5, with the unloading from the excavation of Pit B, it gradually exhibits a convex deformation toward the interior of Pit B. As for diaphragm wall 4#, due to its relatively distant location, the excavation of Pit A has little impact on its deformation. Its lateral displacement only begins to increase gradually during the excavation of Pit B. The second group followed the construction sequence of excavating the larger section first, followed by the smaller section. The horizontal displacement of diaphragm walls 1# to 4# at each excavation stage, plotted against excavation depth, is shown in Figure 14.  
Figure 13: Horizontal displacement diagrams under the condition of small cross section excavation followed by large cross section excavation. During the initial excavation of the larger section (Pit B, Stages 1-2), the horizontal displacement of diaphragm walls 1# and 2# in the smaller-section pit remains nearly unchanged due to the presence of the limited-width soil mass between them. The displacement gradually increases during the subsequent excavation of the smaller-section pit. For diaphragm wall 3#, which is located adjacent to the larger-section Pit B, its displacement initially increases during the deep excavation stage. However, it gradually decreases afterward, shifting toward the subsequently excavated pit. Diaphragm wall 4# consistently exhibits negative displacement throughout the process. The deformation trends of the diaphragm walls in this scenario are similar to those observed in the first group. The displacement of each wall first increases and then decreases, with the overall trend inclining toward the interior of the actively excavated pit. For the third group of synchronous construction sequences, the horizontal displacement curves of diaphragm walls 1# to 4# at each excavation stage, plotted against excavation depth, are shown in Figure 15.  
The horizontal displacements of each wall gradually increase as synchronous excavation progresses. The points of maximum lateral displacement are all located above the excavation face, with deformations developing inward toward their respective foundation pits.