## 5 Results and Discussion
### Mechanical Behavior of Caisson before and after Tilting Anchored  
To investigate the impact of tilting on the structural damage of the caisson, tilted loads of 0.05 MPa, 0.10 MPa, and 0.15 MPa were selected for calculation. Figure 16 shows the calculation contour map of the caisson under tilted loads. It can be observed that due to the relief and dissipation of external loads by the soil, the horizontal displacement of the caisson gradually decreases from shallow to deep after being subjected to tilted loads, and the position of the maximum stress also shifts. When there is no tilting, the maximum tensile stress occurs at the maximum deformation of the lower part of the caisson wall, with a value of approximately 1.47 MPa. As the tilting increases, the point of maximum tensile stress shifts to the intersection of the right caisson wall and the pipe jacking. This is because when the left side of the caisson is tilted, the entire structure is subjected to a moment, which causes the lower right pipe to bear a greater stress. Tilting changes the position of the structure's center of gravity, causing the lower right pipe to bear a greater tilted moment, leading to the maximum stress change. To explore the mechanical behavior of the caisson under different tilted loads, a comparison was made between the horizontal displacement and the maximum stress of the caisson wall. From Figure 17, it can be seen that with the increase in tilted loads, the maximum horizontal displacements of the caisson wall are 16.31 mm, 27.39 mm, and 50.18 mm, marking respective increases of 2.3 times, 3.7 times, and 6.8 times compared to those under without tilted load conditions. Correspondingly, the maximum tensile stresses register 2.07 MPa, 2.57 MPa, and 2.78 MPa, reflecting respective increments of 1.4 times, 1.7 times, and 1.9 times compared to those under no tilted load. The rate of growth gradually diminishes with the escalating tilted loads, attributed to the fact that while initial stress growth might be rapid upon the application of tilted loads, subsequent internal deformation and compaction occur, gradually unveiling the nonlinear characteristics of  
Figure 15: Comparison of mechanical behavior of caisson structures before and after filling: (**a**) void at the middle of the caisson and (**b**) void near the pipe jacking. concrete. Consequently, the response of the caisson wall to external loads slows down, resulting in a gradual reduction in the stress growth rate. The tensile capacity of anchor rods is much higher than that of the foundation materials. Pre-embedded anchor rods can increase the overall stiffness of the foundation, making the foundation structure more stable and effectively reducing the structural damage caused by tilted loads. We use the method of controlling variables to explore the influence of the cross-sectional area and length of the anchor rod on the reinforcement effect when the tilted load is 0.1 MPa. When the length of the anchor rod is 20 m, the cross-sectional size of the anchor rod gradually increases to 1a, 2a, and 4a (a = 2.1 cm\({}^{2}\)). Figure 18 shows a comparison of the mechanical behavior of the caisson under different anchor rod cross-sections. It can be seen that as the cross-sectional area of the anchor rod increases, the relative horizontal displacement of the caisson without anchoring is reduced by 0.15 mm, 0.57 mm, and 1.32 mm, respectively, and the maximum tensile stress of the caisson is reduced by 0.021 MPa, 0.033 MPa, and 0.056 MPa, respectively. The ability to resist deformation under the same tilted load becomes stronger. This is because the increase in the cross-sectional area of the anchor rod increases the friction between the anchor rod and the surrounding soil or rock layers, making it more difficult for the anchor rod to be pulled out or slide, while also being able to bear more load, reduce the impact of the load on the structure, and enhance the stability and bearing capacity of the structure. Figure 16: Calculated cloud for caisson under tilted loads.