## 3 Results  
### Displacement Vectors and Contour Diagram  
With the load-displacement diagram, the displacement of the model during destruction was obtained, and the corresponding image was found, processed, and analyzed by  
Figure 5: Experimental set-up. Figure 11: Vector diagram of soil displacement for MN-15 model. Figure 9: (**a**) \(X-\)direction contour diagram and (**b**) \(Y-\)direction contour diagram of soil displacement for MP\(-\)8 model. Figure 14: (**a**) \(X-\)direction contour diagram and (**b**) \(Y-\)direction contour diagram of soil displacement for MP\(-\)15 model. Figure 12: (**a**) \(X-\)direction contour diagram and (**b**) \(Y-\)direction contour diagram of soil displacement for MN\(-\)15 model. Figure 13: Vector diagram of soil displacement for MP\(-\)15 model. The soil displacement of the MN-8 model was mainly concentrated on the bottom (area 1 and area 2) of the first and second spans and the outer side (area 3) of the hard crust when the cement content was 8% (Figure 6). Meanwhile, the vertical downward displacement of the soil in area 2 increased. In other words, the hard crust was destroyed and extruded the soil downward, contributing to the production of a large displacement downward and a large number of upward displacements. The occurrence of massive soil displacements in Area 3 demonstrated that the connection between the hard crust and the grid structure was destroyed, and the connection extruded the soil outward when subjected to vertical load, enabling the soil to displace upward. The X-direction displacement contour diagram (Figure 7a) revealed that the horizontal displacement of soil was only large at area 1 and area 2, with a maximum of about 0.7 mm. Nonetheless, the displacement near the grid structure slightly changed, with a maximum displacement of only 0.13 mm, indicating that the deformation of the grid structure was small during destruction. In the Y-direction contour diagram (Figure 7b), the downward displacement at the bottom of the hard crust increased significantly to 1.4 mm. This suggested that the soil under the hard crust bore part of the load when the structure was destroyed. The displacement vector diagram of the MP-8 model soil with the increasing thickness of the hard crust is exhibited in Figure 8. Different from the MN-8 model, there was no large displacement of soil in area 3, reflecting that the connection between the hard crust and grid structure was relatively complete during destruction. Nevertheless, a large amount of downward displacement of soil was observed in area 1, implying that the destruction point was still in the hard crust when the structure reached the ultimate bearing capacity. Besides, the distribution law of the contour diagram (Figure 9) was consistent with the MN-8 model. The displacement vector diagram of other structures during destruction in Figure 10 revealed that the soil displacement was still mainly concentrated at the bottom of the hard crust, while the soil displacement near the grid structure was small. When the load was applied to the structure, it was similar to the beam-slab structure, and the hard crust bore tensile force at the bottom during bending. Since the cohesion of cement soil was poor  
Figure 15: Vector diagram of (**a**) SN\(-\)15 model, (**b**) SP\(-\)15 model, (**c**) LN\(-\)15 model, and (**d**) LP\(-\)15 model. when the cement content was small, its tensile capacity was weak, and it was easier to destroy when stretched. Therefore, in the limit state, the hard crust with weak flexural capacity caused the whole structure to be destroyed during bending. In practice, when the cement content is small, it is recommended to add fibers and other materials to the bottom of the hard crust to improve its tensile strength and increase the overall load bearing capacity of the gridded hard crust. Under the same structure, the position of the soil displacement concentration changed with the increase in the cement content.