# Load-Bearing Performance of a Reinforced Fill Structure with Pile Penetration
## 5 Analysis of Results
### The Distribution Law of Pile-Bending Moments
#### 5.2.1 Impact of Different Structure Types  
The bending moment distribution curve of pile of each structure type is shown in Figure 9. The maximum bending moments of the pile for different structural types are listed in Table 11.  
According to the observation in Figure 9, it can be seen that when the vertical load is large, the maximum positive bending moment occurs near the top of the pile, the positive bending moment of the pile decreases along the depth direction, and after reaching the zero point, the negative bending moment of the pile increases along the depth direction of the pile, and the bending moment of the pile shows that the distribution of \"the upper part of the bending moment is positive, and the lower part of the bending moment is negative\", which is basically the same as that of the distribution of the bending moments for foundation piles of bridges on high steep slopes [23; 29].  
Based on the results shown in Figure 9, it is evident that high positive bending moments are observed in both the upper and lower parts of the pile during the initial loading stage. As the loading entered the middle stage, the positive bending moments in the upper portion remained elevated, while there was a significant increase in the middle portion, which peaked at a depth of 300 mm. The smallest bending moments were observed at the depths of 220 mm and 380 mm. In the final stage of loading, the positive bending moments in both the upper and middle portions of the pile increased significantly as the load increased, while the positive bending moments in the upper portion increased more.  
The analysis in Figure 9 shows that the bending moments gradually increase between 140 and 300 mm and then decreased between 300 and 460 mm, peaking at 300 mm. In addition, their bending moments were higher with an increasing load, which was particularly evident at a depth of 300 mm.  
The analysis of Figure 9 and Table 10 reveals that structures with only piles are prone to rotational deformation around the pile end under vertical loads due to the lack of lateral restraint by the horizontal reinforcement material. The structure with flat grain cotton cloth and pile (without the cap of the pile) mainly produces flexural deformation of the pile due to the lateral restraint of the horizontal reinforcement material when the load is small. At higher loads, the rotational deformation of the pile around the pile end is obvious. For the structure with flat grain cotton cloth and a pile (with cap of pile), the cap of the pile enhances the ability to limit the lateral displacement of the top of the pile and makes the bending moment distribution of the pile more reasonable [30].  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Condition** & **Structure Type** &
\begin{tabular}{c} **Maximum Bending** \\ **Moment/(N\(\cdot\)m)** \\ \end{tabular} & **Vertical Load/kN** & **Pile Depth/mm** \\ \hline
1 & Sand & - & - & - \\
2 & Flat grain cotton cloth & - & - & - \\
3 & Pile & 52.61 & 30.0 & 140 \\
4 & Both plain cotton cloth and pile & 42.89 & 45.0 & 140 \\  & (no cap of pile) & & & \\
5 & Both plain cotton cloth and pile & 26.11 & 67.5 & 300 \\  & (cap of pile) & & & \\ \hline \hline \end{tabular}
\end{table}
Table 11: Maximum bending moment value of the pile for different structure types.