# Analysis of Lateral Displacement of Pile Foundation Caused by Large-Diameter Shield Tunneling
## 5 Conclusions  
In this paper, by aiming to understand the influence of shield construction on the displacement of a pile foundation, a mechanical model of the influence of shield construc  
Figure 8: The lateral displacement of the pile foundation under the influence of the shield’s outer diameter. (**a**) \(q=20\) kPa, (**b**) \(q=50\) kPa, (**c**) \(q=100\) kPa, and (**d**) \(q=150\) kPa. Figure 7: The lateral displacement of the pile foundation under the influence of the excavation surface distance and additional thrust of the shield. (**a**) \(q=20\) kPa, (**b**) \(q=50\) kPa, (**c**) \(q=100\) kPa, and (**d**) \(q=150\) kPa. tion on the front pile foundation is established. The displacement of soil during shield construction is obtained using the Mindlin solution. Combined with the horizontal displacement equation of the pile foundation using the Kerr foundation model, the lateral displacement expression of the pile foundation under soil displacement is obtained. Then, through the actual project as a verification example, the finite element model is established by using PLAXIS three-dimensional finite element software, and the theoretical solution expression is solved with MATLAB. The reliability of the theoretical solution is verified by comparing the theoretical and numerical solutions. Finally, the lateral displacement of the pile foundation caused by large-diameter shield tunneling is analyzed using the theoretical solution, and the deformation law of the pile foundation caused by the additional thrust of the shield, excavation distance, and change in the outer diameter of the shield is explored. The conclusions are as follows:  
1. The Mindlin elastic solution and simplified pile-soil foundation model can be used to solve the lateral displacement of the pile foundation caused by the deep-buried shield, which can accurately predict the overall lateral displacement of the pile foundation in front of the shield. MATLAB programming language can be used to realize a simple and efficient calculation, which can provide fast and accurate guidance for shield design and construction. 2. Comparing the numerical and theoretical results of the influence of the shield construction on the displacement of the front pile foundation, for the upper part of the pile foundation, the theoretical calculation is similar to the numerical one. For the lower part of the pile foundation, when the shield is closer to the pile foundation, the theoretical calculation value is larger, and the result is conservative. 3. A larger shield additional thrust and closer excavation face distance will cause larger displacement in the lower part of the pile foundation. In the design, the distance between the excavation face and the pile foundation should be larger than the pile diameter. During construction, when the distance between the excavation face and the pile foundation is small, the shield thrust should be reduced as much as possible to reduce the influence on the pile tip displacement and the pile foundation inclination. 4. Compared with changing the additional thrust of the shield and the distance from the excavation face, changing the outer diameter of the shield has only a small effect on the overall lateral displacement of the pile foundation. In order to control the deformation of the stratum, it is suggested that the distance between the tunnel and the pile foundation should be reasonably determined in the design stage, and the thrust of the shield should be reasonably controlled during the construction. Changing the outer diameter of the shield has a large influence on the displacement of the pile top. The key to controlling the displacement of the pile top and the ground surface is the outer diameter of the shield. It is suggested that the influence of the outer diameter of the shield should be considered when calculating the displacement of the pile top and the ground surface in the design stage. Conceptualization, Y.S. and F.W. ; methodology, F.W. ; software, C.W. ; validation, Z.M. and Y.S. ; formal analysis, F.W.