## 6 Conclusions  
On the basis of the measured results from the Shanghai Zhuyuan Bailonggang Sewage Connection Pipeline Project, this study used the Plaxis\({}^{\text{3D}}\) finite element software to establish a sinking model of the 17# Shaft under the VSM construction method and analyze the soil deformation. The following conclusions were drawn:  
1. In the groove-shaped settlement zone, shear deformation occurs in the soil due to the shearing effect of the shaft wall during shaft sinking, resulting in a groove-shaped settlement. In the heave influence zone, as the depth of the shaft sinking increases, the trend of the bottom heave transitions from a single-peak \"convex\" shape to a double-peak \"concave\" shape. When the shaft sinks to a depth of 0.4 \(H_{\text{m}}\) to 0.9 \(H_{\text{m}}\), the corresponding soil layer is primarily soft clay. With increasing excavation depth, the pore water pressure in the soil inside the pit rises, generating excess pore water pressure, reducing effective stress, and increasing the soil volume, making it more prone to heave deformation. In the heave zone, as the soil within the foundation pit  
Figure 17: Development curve of the bottom heave in relation to distance from the river channel. transitions from silty clay to silt, the amount of heave caused by excavation unloading in this zone is smaller than that in the heave influence zone. 2. In the arch-shaped zone, the soil near the edge of the shaft is directly affected by shaft sinking, exhibiting an arch-shaped deformation similar to that of the shaft wall. This deformation occurs due to the lateral deformation of the shaft wall, which is transmitted through soil shearing, resulting in greater horizontal displacement in the middle portion of the soil, while the displacement in the upper and lower portions is relatively smaller. In the deformation transition zone, as the distance from the shaft increases, the shear force acting on the soil gradually weakens, and the horizontal displacement transitions from an arch-shaped to a cantilever-shaped pattern. The deformation in this zone is characterized by the gradual shift in the maximum horizontal displacement towards the ground surface. In the cantilever bending zone, which is farther from the structure, the horizontal displacement of the soil is primarily influenced by surface deformation. This zone features a cantilever-shaped distribution, where the displacement is largest at the surface and gradually decreases with increasing depth. 3. During the shaft sinking construction, two suspension periods of 10 days and 6 days were used, during which the measured settlement increments accounted for 15.85% and 21.49%, respectively, of the total settlement; the horizontal displacement increments accounted for 27.25% and 27.44% of the total horizontal displacement, respectively. This finding indicates that both construction suspensions exacerbated the soil deformation, with the surface settlement being more sensitive to the excavation depth than horizontal displacement. To minimize the impacts on the surrounding environment and structures, when the excavation depth is between 0.4 \(H_{\text{m}}\) and 0.9 \(H_{\text{m}}\), excavation disturbances should be further reduced, and overex excavation must be strictly avoided. Additionally, in areas where \(L/H_{\text{m}}\) is less than 0.3, the number of environmental monitoring points should be appropriately increased to optimize the refined control of deformation in the areas surrounding the shaft. Conceptualization, P.L. and D.N. ; methodology, P.L. ; software, F.C. ; validation, F.C. ; formal analysis, F.C. ; investigation, P.L. and J.H. ; resources, P.L. and J.H. ; data curation, F.C. ; writing--original draft preparation, F.C. ; writing--review and editing, P.L. and D.N. ; visualization, F.C. ; supervision, D.N. ; project administration, D.N. and J.H. ; funding acquisition, P.L., J.H. and D.N. All authors have read and agreed to the published version of the manuscript.