## 3 Analysis of the Onsite Monitoring Data
### Monitoring of Horizontal Soil Displacement  
After the soil within the lining is cut by the telescopic arm and cutting foot, an imbalance of forces occurs between the inside of the lining and the outside of the lining. This imbalance results in horizontal displacement of the soil as the lining is compressed. Four inclinometers, CX-1 to CX-4, were selected to analyze the horizontal displacement at a depth of 40 m. The distances of these points from the outer edge of the shaft were 2.5 m, 3.2 m, 1.4 m, and 2.9 m. A positive displacement indicates soil movement towards the excavation area, whereas a negative displacement indicates movement away from the excavation. Figure 7 shows the cumulative development curves of horizontal displacement at a depth of 40 m for each monitoring point. The monitoring point CX-2, which was the farthest  
Figure 6: Cumulative settlement development curve of the surface. from the shaft, exhibited the smallest cumulative horizontal displacement at 9.86 mm. In contrast, CX-3, the closest to the shaft, experienced the largest cumulative displacement, reaching 33.77 mm after construction was completed. During the first construction pause and second construction pause, the cumulative horizontal displacement at CX-3 increased by 4.48 mm and 10.86 mm, respectively, accounting for 13.26% and 32.16%, respectively, of the total displacement. The monitoring results at CX-1 displayed a trend similar to those at CX-3, whereas at CX-2 and CX-4, the rate of horizontal displacement growth significantly slowed during the two pause periods. A geotechnical investigation revealed significant variations in the thickness of the soft clay layer ()\({}_{32}\) near a depth of 40 m, resulting in notable differences in the response of the soil to stress relief. Owing to the pronounced rheological characteristics of soft soil, stress relief during construction significantly influences the rate of displacement growth. Consequently, despite some points being closer to the shaft, distinct thickness differences across the soil layers caused noticeable fluctuations in the displacement monitoring data. To investigate the changes in the surrounding soil during shaft subsidence, Figure 8 depicts the horizontal displacement development trend of CX-3, the point closest to the shaft, during both the shaft sinking period and the pit bottom construction period. Figure 8: Horizontal displacement development curve for CX-3: (**a**) shaft sinking period and (**b**) pit bottom construction period. Figure 7: Cumulative horizontal displacement development curve at the 40-metre depth measurement point. Before the shaft sinks, the horizontal displacement of the shallow soil is limited by the retaining wall and the weight of the VSM equipment. The horizontal displacement development curve for CX-3 during the shaft sinking period is shown in Figure 8a. The location of the maximum horizontal displacement value shifted downwards as the shaft sank, converging at a depth of 18.5 m, where the horizontal displacement was 31.13 mm. During the construction pause, influenced by the time--space effect, the horizontal displacement continued to increase, with a maximum increase of 12.31 mm, accounting for 39.54% of the total horizontal displacement during the shaft sinking phase. Figure 8b shows the horizontal displacement development curve for CX-3 during the pit bottom construction period. After the completion of slurry replacement, the maximum horizontal displacement reached 45.18 mm, with a peak value at 17.5 m, which was slightly greater than the previous value at 18.5 m. During the second construction pause, the maximum horizontal displacement increment was 12.4 mm, accounting for 27.44% of the maximum horizontal displacement during the pit bottom construction phase. During the pause, the surrounding soil near the shaft bottom experienced rapid inwards deformation, but the rate of horizontal displacement growth slowed during the bottom cleaning phase, and during slurry replacement, horizontal displacement tended to stabilize.