# Force Analysis of Circular Diaphragm Wall Based on Circular Cylindrical Shell Theory
## 7 Results and Discussion
### Vertical Bending Moment of Circular diaphragm Wall  
The vertical bending moments of the circular diaphragm wall obtained through the CCSTCM, FENSM and site monitoring are shown in Figure 12. From Figure 12, we can observe that the vertical bending moments of the circular diaphragm wall obtained through both the CCSTCM and FENSM increase first to the maximum vertical plus bending moments, then to the maximum vertical minus bending moments, and finally decrease to 0 with the increase in depth in different working conditions. The maximum vertical plus bending moments and maximum vertical minus bending moments increase gradually with the increase in excavation depth, and the positions of the maximum vertical plus bending \begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Method**} & \multirow{2}{*}{**EMRD**} & **PCS** & **P** & **EMCS** & **PCS** & **P** & **EMVBPM** & **PCS** & **P** & **EMVMBM** & **PCS** & **P** \\  & & **//m** & /MPa & /\% & /m & /\% & /m & /\% & /m & /\% & /m \\ \hline Site monitoring & 11.6 & - & 35 & 2.973 & - & 29 & 2074.5 & - & 34 & \(-\)1328.1 & - & 46 \\ \hline CCSTCM & 10.1 & 87.1 & 32 & 2.521 & 84.8 & 32 & 1632.2 & 78.7 & 32 & \(-\)1269.8 & 95.6 & 46 \\ \hline FENSM & 9.7 & 83.6 & 32 & 2.375 & 79.9 & 32 & 1518.0 & 73.2 & 32 & \(-\)1183.9 & 89.1 & 46 \\ \hline \hline \end{tabular} Note: EMRD represents the extremum of the maximum radial displacements; P represents the position of the extremum; EMCS represents the extremum of the maximum circumferential stresses; EMVPBM represents the extremum of the maximum vertical plus bending moment; EMVMBM represents the extremum of the maximum vertical minus bending moment; PCS represents the percentage compared with the SMR.  
\end{table} 
Table 4: The extremum comparison of the results. moments and maximum vertical minus bending moments decline gradually and then tend to be stable with the increase in excavation depth. The TCR are slightly larger than the NSR. Except for Working Conditions 1 and 2, in other working conditions, the vertical bending moments of the circular diaphragm wall obtained through the site monitoring first increase to the maximum vertical plus bending moments, then to the maximum vertical minus bending moments, and finally decrease to 0 with the increase in depth. The maximum vertical plus bending moments and maximum vertical minus bending moments increase gradually with the increase in excavation depth, and the positions of the maximum vertical plus bending moments and maximum vertical minus bending moments decline gradually and then tend to be stable with the increase in excavation depth. Combined with Table 4, it can be further determined that the extremum of the maximum vertical plus bending moments obtained from the site monitoring is 2074.5 kN\(\cdot\)m, which occurs 34 m from the top of the circular diaphragm wall in W 15. The extremum of the maximum vertical plus bending moments obtained from the CCSTCM is \(-\)1269.8 kN\(\cdot\)m, which is 95.6% of the SMR, and occurs 46 m from the top of the circular diaphragm wall in W 15. The extremum of the maximum vertical plus bending moments obtained from the FENSM is 1518.0 kN\(\cdot\)m, which is 73.2% of the SMR and 93.0% of the TCR, occurs 32 m from the top of the circular diaphragm wall in W 15 also. The extremum of the maximum vertical minus bending moments obtained from the site monitoring is \(-\)1328.1 kN\(\cdot\)m, which occurs 46 m from the top of the circular diaphragm wall in W 15. The extremum of the maximum vertical minus bending moments obtained from the CCSTCM is \(-\)1269.8 kN\(\cdot\)m, which is 95.6% of the SMR, and occurs 46 m from the top of the circular diaphragm wall in W 15. The extremum of the maximum vertical minus bending moments obtained from the FENSM is \(-\)1183.9 kN\(\cdot\)m, which is 89.1% of the SMR and 93.2% of the TCR, occurs 46 m from the top of the circular diaphragm wall in W 15 also.