## 3 Results and Discussion
### Numerical Analysis of Spatiotemporal Effect
#### 3.2.3 Surface Settlement Around the Pit  
Based on the vertical deformation of the soil around the pit (Figure 11), it was evident that after the completion of pit excavation, varying degrees of settlement occurred on the surface outside the pit. The surface settlement on both sides of the pit was symmetrical, increasing with distance from the pit edge before decreasing. Settlement on the shorter sides was less than that on the longer sides. Through the selection of monitoring points along the pit section, the comparison between monitored surface settlement data and simulation results, shown in Figure 12, revealed that the simulated surface settlement  
Figure 9: Horizontal displacement of diaphragm wall of Huaxi Park Station foundation pit.  
followed a similar pattern to the monitoring data, initially increasing and then decreasing from the edge of the pit, forming a \"concave\"-shaped curve, with the maximum settlement point moving away from the pit edge line. The surface settlement reached its maximum at about 12 m from the pit edge, which differs from the commonly observed pattern, where maximum settlement typically occurs at a distance of approximately 0.2 to 0.3 times the excavation depth [3; 5; 40; 41]. This discrepancy may be attributed to the creep behavior and high compressibility of the soft soil, which allowed for the settlement to extend further from the pit edge, especially when the excavation depth was significant. This aligns with findings in studies by [PERSON] et al. (2025) and [PERSON] et al. (2022), where maximum settlement in soft soils was observed farther from the excavation boundary [34; 35]. After fluid-solid coupling and rheological calculations of the mucky soil, the overall simulation results for the pit's standard section aligned closely with the on-site monitoring results, with the maximum difference in deformation at the points of the greatest surface settlement not exceeding 5 mm. In the simulation, only the effects of overload were considered, while live loads such as construction vehicles were not taken into account. Relevant studies have shown that live loads, such as those from construction vehicles, can significantly impact surface settlement [5; 35]. The simulation results for the end wells were smaller in scope than the monitoring data, which may be attributed to the frequent movement of heavy construction vehicles and public vehicles near the end wells at the actual construction site, leading to excessive surface settlement. Therefore, to protect the surrounding environment during actual construction, the monitoring of surface settlement at each excavation stage should not be neglected, especially at locations where the maximum values of surface settlement may occur during various stages.  
Regarding the surface settlement outside the pit and the lateral deformation of the diaphragm walls, a comparative analysis of simulation results and monitoring data revealed that in the standard section of the pit, the rheological constitutive model and parameters selected for mucky soil accurately reflected the deformation pattern of the mucky soil pit, and can be used for deformation prediction in such pits.  
Figure 10: Horizontal displacement of diaphragm wall (CX5): (**a**) horizontal displacement versus depth curve; (**b**) variation curve of maximum horizontal displacement with construction sequence. (Construction sequence: 1—arrangement of the first steel support; 2—arrangement of the second steel support; 3—arrangement of the third steel support; 4—arrangement of the fourth steel support; 5—arrangement of the fifth steel support; 6—completion of the footing pouring.)  
Figure 11: Vertical displacement after the completion of excavation: (**a**) surface settlement outside the pit; (**b**) vertical displacement.  
Figure 12: Surface settlement outside the pit after the completion of excavation: (**a**) DB4; (**b**) DB6; (**c**) DB1.