# Prediction of Ground Deformation during Pipe-Jacking Considering Multiple Factors
## 4 Application to Case Study
### Validation
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \(P\) (MPa) & \(f\) (MPa) & \(T\) (MPa) & \(\eta\) (\%) & \(\mu\) & \(G\) (MPa) & \(h\) (m) & \(L\) (m) & \(R\) (m) & \(R_{s}\) (m) \\ \hline
0.30 & 0.24 & 0.08 & 2 & 0.31 & 2.4 & 18.9 & 5 & 2.1 & 2.08 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Construction parameters for Line 1 and Line 3. Figure 10: Ground surface settlements above Line 1 and Line 3. Figure 12 shows the settlements at the depth of 7.4 m above Line 1 and Line 3. The proposed method matches better to the settlement above Line 1. The field data show that the underground movement is more irregular than the ground surface settlement. It indicates that the disturbance caused by pipe-jacking is more obvious in the underground region. The influence of the grouting pressure on ground movement will reduce with increasing distances. The predicted results show a good consistency to the monitored results after the jacking machine crossed through the monitoring point. Considering the grouting pressure in the proposed method leads to an improvement in prediction effectiveness, as compared to the other two methods. Figure 13 shows the ground surface settlements adjacent to Line 1 and Line 3. The predicted results are closer to the results from the two middle monitoring points. The field data indicate that the ground settlements between the pipe-jacking (S3 and S4) is larger than those at the outer sides. As the middle region is disturbed by the construction of Line 1 and Line 3, the settlement phenomenon can be explained by the superposition theory. The method in this study is proposed based on the single line of pipe-jacking and has not considered the settlements caused by adjacent construction. Moreover,  
Figure 11: Proportions of influence factors on overall ground settlement. Figure 12: Ground settlements at depth of 7.4 m below surface. all the prediction methods overestimate the upheaval of ground surface before the jacking machine arriving at the monitoring points. After the arrival of the jacking machine, the results of the proposed method are better than those of the [PERSON] method [74] and the [PERSON] et al. method [61]. Figure 14 shows the variation of ground settlements with the monitoring depth increasing. The predicted results under the ground are consistent with the field data in general. The upheaval of ground in a deeper position is more remarkable. The difference between calculated results and monitored values becomes less at this depth. After the arrival of the jacking machine, the same phenomenon indicates that the calculated ground settlement becomes smaller than those calculated by other two methods is found. Generally, the underground settlements are smaller than the ground surface settlements. In addition, the values of settlements decrease with the increase of monitoring depth. Figure 14: _Cont_. Figure 13: Ground settlements adjacent to Line 1 and Line 4 at ground surface. Based on above comparisons between calculated results and field observations, the effectiveness of the proposed method for ground settlement prediction was validated. The proposed method can predict the ground settlement caused by the pipe-jacking. The better effectiveness compared to the other two methods can be attributed to the consideration of grouting pressure. The slurry grouting can mitigate the ground loss, so that the prediction effectiveness after the arrival of the jacking machine is better than that of the other methods. However, the calculated upheaval before the arriving of jacking machine is larger than the field value. Some limitations should be pointed out, which are expected to be improved in future projects. The proposed method is based on the analysis in homogeneous and isotropic condition. However, the geological conditions are always heterogeneous and anisotropic in field cases. The method used in this study was to calculate the average value as the geological parameter, which may attribute to the difference between calculated results and field results.