## 2 Study on the Deformation under Static Forces  
### Study on the Deformation Mode  
Many experts and scholars have performed relevant research on the deformation mode of modular reinforced soil retaining walls under static action (Figure 3), which is mainly divided into tilting types (Figure 3a) and bulging types (Figure 3b).  
[PERSON] et al. [21] introduced deformation monitoring of a 6.1 m-high modular reinforced soil retaining wall in Illinois, USA, after completion and after loading. The monitoring results are shown in Table 1.  
[PERSON] et al. [22] introduced the deformation response of reinforced soil retaining wall abutment structures completed near Denver, Colorado, in 1999 during the construction period. The maximum outward displacements of Section 200, Section 400, and Section 800 are 7, 9m and 10 mm, respectively. Among them, the maximum deformation positions of Section 200 and Section 800 are equal to 2/3 of the wall height, and the deformation mode is bulging. The maximum deformation position of Section 400 is at the top of the wall, and the deformation mode is an outward-dip type. This may be due to the difference in the deformation modes caused by different construction seasons and different construction processes.  
[PERSON] et al. [23,24] and [PERSON] et al. [25,26] introduced four 3.6 m high reinforced soil retaining walls constructed by the Royal Canadian Military Academy, and four models were different due to different spacings and stiffnesses of the reinforcement. In the observation after completion and after loading, the maximum deformation position is approximately 2.7 m high, and the deformation mode bulges.  
[PERSON] et al. [27] developed a model with dimension of 1.4 m (length) \(\times\) 1.4 m (width) \(\times\) 2.0 m (height) to study the deformation mode of reinforced soil columns.  
\begin{table}
\begin{tabular}{c} **Deformation** \\ **Mode** \\ \end{tabular} \\ \hline
107 days after completion & 3.07 m & 19.56 mm & Bulging & 6.1 m & 28.7 mm & Tilting \\
370 days after loading & 3.07 m & 91.44 mm & Tilting & 6.1 m & 60.71 mm & Tilting \\ \hline \hline \end{tabular}
\end{table}
Table 1: Deformation after completion and loading.  
Figure 3: Horizontal deformation mode of the reinforced soil retaining wall.  
The deformation modes under different loads, different ultimate tensile forces of the reinforcement, and different vertical spacings were obtained. The test results show that the maximum lateral deformation occurs at a height of one-third from the top regardless of whether the veneer is included in the test process, and the overall deformation trend is inclined.  
[PERSON] et al. [28] made a retaining wall with dimensions of 1.0 m (length) \(\times\) 0.54 m (height) to analyze the influence of the distance between the strip foundation and wall panel on the deformation characteristics of the reinforced retaining wall. The results show that when the foundation deviation distance D is less than 0.5 H, the top deformation of the retaining wall is the largest, and the overall deformation trend is inclined. When D is 0.6H and 0.8H, the deformation of the upper part of the retaining wall is the largest, and the overall trend changes to bulging.  
In conclusion, due to different factors, such as the height of the retaining wall, the length of the reinforcement, the spacing of the reinforcement, the stiffness of the reinforcement, the construction season and the construction sequence, the modular reinforced soil retaining wall has different deformation modes and deformation amounts. Therefore, it is necessary to evaluate the applicability and accuracy of existing deformation calculation methods.