## 4 Results
### Structural Response Inside the Pit  
#### 4.2.1 Diaphragm Wall  
Figure 6 depicts the horizontal displacement contour maps of the diaphragm wall after construction. As shown in Figure 6, the diaphragm walls show a deformation pointing into the pit, and the deformation distribution has obvious spatial effects. The displacement corresponding to the long side is greater than that corresponding to the short side, and the sudden change in shape of the local position of the foundation pit causes a reduction in the maximum horizontal deformation of the retaining structure. However, since the roof of the first underground floor is built after the excavation of the first underground floor is completed, the top of the diaphragm wall shows a large deformation, which is different from the small deformation of the top of the diaphragm wall adopting the covered top-down method [17; 26]. Figure 7 shows the horizontal displacement distribution of the diaphragm wall at the monitoring section III-III for different construction processes. It can be found that the top deformation of diaphragm wall is larger than others at the end of process 4, which is different from the deformation trend of the conventional covered top-down method [17; 26]. This may be owing to the fact that the construction of the pit is equivalent to a cantilever-supported excavation during process 4, resulting in a large deformation at the top of diaphragm wall, whereas when the subsequent processes are carried out, the  
Figure 4: Results of monitoring data and numerical simulation of ground settlement. (a) DB-1: (b) DB-2. Figure 5: History curves of the settlement of surrounding buildings. (a) JC-1: (b) JC-2. top of the diaphragm wall is completely constrained, and the horizontal displacement is no longer increasing following the completion of the roof of the first underground floor. During process 5, the position where the maximum deformation occurs shifts to 6.0-7.0 m below the ground level. In the subsequent construction, the floor slab plays a great supporting role, and the deformation value at this portion remains almost unchanged. But the position of maximum deformation gradually moves downwards as construction continues, the horizontal deformation distribution along the depth changes from \"single peak\" to \"double peaks\", and the peak value of displacement of the lower part appears at a depth of 22.5 m below the ground (about 88% of the excavation depth of the pit). With the subsequent excavation, the position of the maximum horizontal displacement of the diaphragm wall does not change, but its displacement value is increasing. In process 10, only the superstructure was constructed, which has little impact on the horizontal displacement of the diaphragm wall (as shown in Figure 7, the curve of process 10 almost completely overlaps with that of process 9), and the maximum horizontal displacement still appears at a depth of 22.5 m after the whole construction. Therefore, more attention should be paid to the deformation of this position of 22.5 m below the ground (about 88% of the excavation depth of pit) during construction to avoid damage to the diaphragm wall, and if necessary, additional support can be adopted to reduce the deformation of this location. Additionally, as the design depth of the diaphragm wall is 36.5 m, the bottom of the diaphragm wall is closer to the bottom slab of the 5 th underground floor (only 11.0 m). With the progress of construction, the constraint of stratum on the bottom of the diaphragm wall gradually decreases, resulting in a larger deformation at the bottom of the diaphragm wall. Figure 6: Displacement contour maps of diaphragm wall. (**a**) The X-direction: (**b**) the Y-direction. Figure 7: Horizontal displacement of diaphragm wall at section III–III.