## 4 Conclusions  
This study aimed to investigate the spatiotemporal effects of deep excavation in mucky soft soil at the Huaxi Park Station foundation pit of Suzhou Metro Line S1. Through field monitoring and numerical simulations, the deformation characteristics of pit retaining structures, surface settlement, and internal support forces were analyzed. A three-dimensional numerical model, incorporating the CVISC viscoelastic-plastic model to account for the creep characteristics of the mucky strata, was developed. The main conclusions can be drawn as follows:  
(1) As the construction sequence progressed and the depth of excavation continuously increased, the horizontal displacement of the diaphragm walls showed an approximately linear increase. When the excavation approached the bottom of the pit, sudden changes in the displacement of the retaining walls were likely to occur. After the completion of excavation, the deformation of the diaphragm walls continued to increase over time, reflecting, overall, the significant time-dependent deformation characteristics of the muck soil pit during excavation;  
(2) The surface settlement on both sides of the pit was symmetrical, moving outward from the edge of the pit, and the surface settlement outside the pit first increased and then decreased, with the maximum settlement exceeding 40 mm. Excavation was the main factor causing surface settlement outside the pit, which directly caused the lateral deformation of the diaphragm walls, thereby causing surface settlement. Besides the instantaneous deformation caused by excavation, surface settlement was also controlled by the timing of excavation, with the deformation over time being quite significant;  
(3) The surface settlement on both sides of the pit exhibited a \"trough\" distribution pattern and reached its maximum value at about 12 m from the pit edge. Therefore, it was feasible to consider reinforcing the soil within a certain range of this location (especially the mucky layers), such as through stone dumping compaction or planar grid-shaped cement mixing piles to \"lock the silt\";  
(4) When soft soil layers were excavated, the entire diaphragm wall displacement rate was relatively fast. Before this construction stage, the mud within the excavation range could be reinforced or temporarily supported by several more struts. During the construction stage, it was advisable to accelerate the speed of the excavation of soft soil layers and increase the frequency of monitoring diaphragm wall displacement;  
(5) The retaining structure and surface settlement deformation induced by the creep of soft soil and spatial effect of the excavation sequence were considered in this case, which provided critical insights for similar deep excavation projects in mucky soft soil by providing guidance on design standards and monitoring strategies for similar geological conditions;  
(6) The simulation primarily focused on the deformation and support forces during the excavation process but did not further explore the evolution of the deformation parameter under the long-term impact of consolidation settlement on the stability of the foundation pit, which can be further studied in future research;  
(7) Future research could explore the use of machine learning and data-driven models to predict soil behavior and optimize excavation plans. By leveraging historical and real-time monitoring data, these models could improve prediction accuracy and enable real-time dynamic adjustments during the excavation process. Meanwhile, incorporating real-time monitoring technologies coupled with machine learning models for prediction can be introduced in a future study. Methodology, J.W., Q.W., Y.L. and X.L. ; Software, Y.L. and H.L. ; Validation, J.W., Y.L., X.L., G.L., S.D., L.Z., H.L. and M.A.H.b.H. ; Formal analysis, J.W., Y.L., G.L., S.D., L.Z., H.L. and M.A.H.b.H. ; Investigation, J.W., G.L., S.D., L.Z., H.L. and M.A.H.b.H. ; Resources, J.W., X.L., S.D. and L.Z. ; Data curation, X.L., G.L., S.D. and M.A.H.b.H. ; Writing--original draft, J.W. and Y.L.