# Analysis of the Working Performance of a Back-to-Back Geosynthetic-Reinforced Soil Wall
## 3 Results and Discussion  
### Post-Construction Performance of the BBGRSW  
#### 3.1.1 Lateral Deformation of the BBGRSW  
The lateral deformation of the wall during the 72 months after completion is shown in Figure 6. During this period, the lateral deformation of the BBGRSW on-site never exceeded 5.0 mm. No sudden deformation appeared, and the deformation remained steady. The post-construction lateral deformation remained stable after 72 months of construction. The measured maximum deformation on-site was 3.94 mm, which is approximately 0.0365% of the wall height and much less than the 4% limitation [13; 23] or the deformation results investigated by [PERSON] and [PERSON] [8; 9; 24; 25]. As seen in Figure 6, the lateral deformation of the wall under a load of 54.1 kPa was much larger than that under 17.3 kPa, especially at the position near the top, which indicated that the applied load could have a major impact on the post-construction deformation of the BBGRSW.  
As shown in Figure 7, the post-construction deformation on the left blocks and right panel along the height indicated that the deformation under the load of 54.1 kPa at the top was approximately 467.8% of that under 17.3 kPa. The deformation distribution of the wall showed that the load on the top of the wall had a significant influence on the deformation of the upper wall and the panel at the top of the wall had an obvious outward inclination that also caused the wall to move outward. The deformations of the left blocks and right panel were reasonable based on the model test attributed to [PERSON] and [PERSON] et al. [26; 27]. According to the model test results, the deformation pattern was linear for the blocked wall, in which the lateral deformation increased along the height and peaked at the top.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Items** & **Filling Soil** & **Clayey Silts** & **Gravel Soil** & **Bed Rock** \\ \hline Model & Hardened soil Small & Soft soil & Mohr–Coulomb & Linear elastic \\ Saturated unit weight (kN\(\cdot\)m\({}^{-3}\)) & 19.2 & 22.4 & 20 & - \\ Peak plane strain friction angle (\({}^{\circ}\)) & 37.3 & 25.8 & 40.0 & - \\ Cohesion (kPa) & 3.1 & 9.2 & 0 & - \\ Angle of dilatancy (\({}^{\circ}\)) & 7.3 & - & - & - \\ Modified compression parameter & - & 0.27 & - & - \\ \(E_{50}^{ref}\) & 4000 & - & - & - \\ \(E_{ext}^{ref}\) & 5554 & - & - & - \\ \(E_{int}^{ref}\) & 17,000 & - & - & - \\ \(m\) & 0.5 & - & - & - \\ \(G_{0}\) & 30,000 & - & - & - \\ \(70.7\) & 0.0004 & - &The deformation pattern was also different between both sides. This was because the panel was different; not only was the geogrid buried among the layers of the blocks, but also the modular blocks were connected with rebar from the top to the bottom, which resulted in a much greater stiffness of the blocked panel compared with the wrapped and concrete-faced panel.  
The vertical deformation of the wall during the 72 months after completion is shown in Figure 8. During this period, the compressive deformation of the wall exhibited a large increase over the first 9 months, which was approximately 86.7% of the total vertical deformation. It then slowed down to approximately 35.0 mm during the last 12 months of the 5 years after the wall was completed. The post-construction deformation was approximately 0.39% of the wall height, which was approximately 35.19% (i.e., 100 mm)  
Figure 6: Post-construction deformation of the left blocks and right panel over time. (**a**) Lateral deformation of the left blocks; (**b**) lateral deformation of the right panel.  
Figure 7: Post-construction deformation of the left blocks and right panel by FEM along the height. (**a**) Lateral deformation of the left blocks; (**b**) lateral deformation of the right panel.  
of the allowable settlement in the Chinese Code for the Design of High-Speed Railways (TB 10621-2014) [28]. This indicated that the deformation was suitable for its application in high-speed railway subgrades.