## 4 Numerical Simulation
### Simulation Results and Comparative Analysis  
#### 4.2.1 Comparison of Simulation Results  
Several primary sections are chosen for analysis based on the monitoring sites, and properly characterize the 3D spatial stress and deformation of the foundation pit. The sections are shown in Figure 12. The HH section on the long side and the KK section on the short side of the foundation pit are selected to compare ground settlements, horizontal displacement of the pile's top, and the horizontal displacement of piles at various depths. The results are shown in Figures 13-15. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Property** & **Type** & **Row of Piles** & **Concrete Surface** \\ \hline equivalent thickness, \(h\) (m) & 0.955 & 0.20 \\ Unit weight, \(\gamma\) (kN-m\({}^{-3}\)) & 25 & 25 \\ Elastic modulus, \(E/\mathrm{GPa}\) & 32.5 & 30 \\ Poisson’s ratio, \(v\) & 0.3 & 0.3 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Main parameters of bored pile. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Property**Number & **1 st Anchor** & **2 nd Anchor** & **3 rd Anchor** & **4 th Anchor** & **5 th Anchor** & **6 th Anchor** \\  & **Cable** & **Cable** & **Cable** & **Cable** & **Cable** & **Cable** \\ \hline Rod body type & 7\(\Phi\)510.8 & 5\(\Phi\)510.8 & 5\(\Phi\)510.8 & 5\(\Phi\)510.8 & 5\(\Phi\)510.8 & 5\(\Phi\)510.8 & 5\(\Phi\)510.8 \\ Incident angle (\({}^{\circ}\)) & 15 & 15 & 15 & 15 & 15 & 15 \\ LFS (m) & 12 & 12 & 12 & 8 & 8 & 8 \\ EAFS (\(\times\)10\({}^{4}\) kN) & 8.042 & 5.743 & 5.743 & 5.743 & 5.743 & 5.743 \\ LAS (m) & 16 & 12 & 12 & 8 & 8 & 8 \\ EAAS (\(\times\)10\({}^{4}\) kN) & 5.667 & 5.437 & 5.437 & 5.437 & 5.437 & 5.437 \\ borehole diameter (m) & 0.15 & 0.15 & 0.15 & 0.15 & 0.15 & 0.15 \\ Prestress (kN) & 100 & 100 & 100 & 100 & 100 & 100 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Main parameters of prestressed anchor cable. Figure 11: 3D mesh of the model. Figure 12: The positions of section. Figure 13: Ground settlement: (**a**) HH section of the long side, (**b**) KK section of the short side. As can be seen from Figure 13, the measured values of ground settlement at sections HH and KK are both less than the calculated values and the curve of settlement morphology in the shape of \"groove\" and the maximum settlement occurs around 6 m away from the edge of the pit. The simulated maximum values of sections HH and KK are 11.25 mm and 5.83 mm, respectively, more than 0.31 mm and 0.20 mm from the measured values. Figure 14 shows that the horizontal displacement of the pile top at the pit corner is obviously less than that at the middle, no matter the measured value or the simulated value. Although the simulated values are slightly larger than the measured values, the deformation trends are consistent. The result illustrates that the spatial effect of pit deformation through the 3D simulation is correct. It can be seen from Figure 15 that the measured horizontal displacements of the pile at sections HH and KK are slightly smaller than the calculated value. The deformation curve is the same trend for both. The curve of pile at section HH is in the shape of a \"belly drum\", in which the bottom is very small and the middle and upper are large. The curve of the horizontal displacement of the pile at section KK is in the shape of a \"bow\". The maximum horizontal displacements simulated for sections HH and KK were 18.44 mm and 12.32 mm, which were located 6.5 m and 7.5 m below the pile top, respectively. The measured maximum horizontal displacements were 17.43 mm and 11.38 mm, which occurred at 7.0 m and 9.0 m below the pile top, respectively. Figure 14: Horizontal displacement of piles top: (**a**) HH section of the long side, (**b**) KK section of the short side. Figure 15: Horizontal displacement of piles at various depths: (**a**) HH section of the long side, (**b**) KK section of the short side.