## 2 Materials and Methods
### Theoretical Analysis of the Role of Pile Excavation on the Influence of Pipelines
#### 2.2.1 Soil Deformation Outside the Pile Excavation Hole and Influencing Factors  
With the removal of the soil inside the pile foundation during pile excavation, the surrounding structure is displaced toward the center of the pile foundation, which leads to the displacement of the soil outside the pile foundation in a horizontal direction. Therefore, the horizontal stress in the soil outside the pile foundation structure decreases, and the corresponding shear force in the vertical direction increases, resulting in the appearance of a plastic region in the soil above the pile foundation. Relative to the deformation of the upper enclosure structure and the soil body of the pile foundation, the lower soil body in  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Piers**} & \multicolumn{2}{c}{**HBR400**} & \multicolumn{2}{c}{**HPB300**} & \multirow{2}{*}{**C30**} & \multirow{2}{*}{**\(\mathbf{\Phi}57\times\mathbf{3}\) mm**} \\  & & & **Steel Reinforcing Bar** & & **Reinforcing Bar** & \\ \cline{3-6}  & & **\(\mathbf{\Phi}\)28 (kg)** & \(\mathbf{\Phi}\)**25 (kg)** & \(\mathbf{\Phi}\)**16 (kg)** & \(\mathbf{\Phi}\)**10 (kg)** & **(m3)** & **(m)** \\ \hline \multirow{4}{*}{Left lane of Wengcun No. 1 Bridge} & 3\# & 26,852.65 & 1892.15 & 254.7 & 4587.2 & 492 & 800 \\  & 4\# & 65,464.7 & 4909.6 & 530.9 & 10,482 & 1488.2 & 1600 \\  & 5\# & 76,090.7 & 5646 & 610.5 & 11,872.8 & 1754.3 & 1880 \\  & 6\# & 26,852.65 & 1892.15 & 254.7 & 4587.2 & 492 & 800 \\ \hline \multirow{4}{*}{Right lane of Wengcun No. 1 Bridge} & 4\# & 36,589.9 & 2680.6 & 361 & 5738.6 & 674.9 & 1088 \\  & 5\# & 130,929.3 & 9819.2 & 1061.8 & 20,964.1 & 2976.4 & 3200 \\  & 6\# & 130,929.3 & 9819.2 & 1061.8 & 20,964.1 & 2976.4 & 3200 \\  & 7\# & 26,795.5 & 1576.8 & 212.4 & 4075.5 & 410.2 & 672 \\ \hline Total & & 516,388.7 & 38,235.7 & 4347.8 & 83,271.5 & 11,264.4 & 13,240 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Quantity table for pile work materials for the main bridge of Wengcun No. 1 Bridge.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Piers**} & \multicolumn{2}{c}{**Root Number**} & \multicolumn{2}{c}{\(\mathbf{\Phi}\)**1.8 m Single**} & \multirow{2}{*}{**Root Number**} & \multirow{2}{*}{**\(\mathbf{\Phi}\)**2.2 m Single**} \\  & & & **Pile Length (m)** & & **Pile Length (m)** \\ \hline \multirow{4}{*}{Left lane of Wengcun No. 1 Bridge} & 3\# & 8 & 24 & \\  & 4\# & & & 10 & 39 \\  & 5\# & & & 10 & 46 \\  & 6\# & 8 & 24 & & \\ \hline \multirow{4}{*}{Right lane of Wengcun No. 1 Bridge} & 4\# & 8 & 33 & \\  & 5\# & & & 10 & 39 \\  & 6\# & & & 10 & 39 \\  & 7\# & 8 & 20 & & \\ \hline Total & & 32 & & 40 & \\ \hline \hline \end{tabular}
\end{table}
Table 1: Quantity table for pile work for the main bridge of Wengcun No. 1 Bridge.  
the excavation surface inside the pile foundation produces horizontal displacement under the action of excavation. Furthermore, concerning the lower soil body under the action of excavation, the horizontal stresses and vertical shear increase accordingly, resulting in a localized plastic zone in the area of the lower passive soil body of the pile foundation. When the pile foundation is set in a soil layer with poor soil quality, in the excavation process, as a result of the surrounding displacement and deformation and the joint action of the outer soil body and the lower soil body, the outer soil body of the pile foundation will slide to the inner side of the hole during the excavation process, resulting in the settlement of the outer soil body during the excavation process of the pile foundation.