## 4 Analyses of Test Results
### Horizontal Displacement of Wall  
Figure 14 shows the maximum horizontal displacement measured at the top of the wall (height 4.9 m) with respect to the load, which was obtained from four cross section with different reinforcement lengths and wall-backfill connection methods. Horizontal  
Figure 13: Estimation of bearing capacity by P-S curve method.  
displacement in the low load of 417 kPa or less occurred in the order of 2R \(>\) 1R \(>\) 1L \(>\) 2L. Because the largest displacement occurred in the wind-bold-wire type and the smallest in the welded type, the horizontal displacement of the wall at the low load was considered to be greatly influenced by the wall-backfill connection method.  
The horizontal displacement of the wall at the maximum load (1000 kPa) occurred in the order of 1R \(>\) 2R \(>\) 1L \(>\) 2L, which tends to decrease because the length of the reinforcement is longer, and the horizontal displacement of the 1R and 2R sections is reversed above a load of 500 kPa. Because the horizontal behavior of the wall changed at a load similar to the yield point of the load-settlement curve, this phenomenon may be highly related to the yield of soil and the tension of the reinforcement in the reinforcement area. As the plastic deformation of the soil proceeds, the effect of the reinforcement on the horizontal displacement of the wall increases. Moreover, a longer reinforcement length decreases the deformation of the wall; thus, the load-wall horizontal displacement curve appeared, as shown in Figure 14.  
The wall-backfill connection method had a governing effect on the horizontal displacement of the wall at a low load below the yield point, which was estimated from the load-settlement curve; the length of the reinforcement had a governing effect on the load above the yield point. The smallest horizontal displacement occurred in the 2L section with reinforcement vertical spacing of 40 cm and a reinforcement length of 2 m. A similar horizontal displacement occurred in the 1L and 2R sections, which have the same reinforcement length of 1.75 m, but different vertical spacings of 0.3 and 0.4 m, respectively, above the load of 653 kPa. Thus, the length of the reinforcement, instead of the vertical spacing, has a greater influence on the horizontal displacement of the wall.  
Figure 15 shows the horizontal displacement with respect to the wall height of each load step. In all four sections, the largest displacement occurred in the upper part of the wall. In the 1L section, the wall displacement pattern exhibits an outwardly concave shape, and in other sections, they exhibit an outwardly convex shape. The characteristic of horizontal displacement in the 1L section is that the wall is outwardly concave, unlike previous studies [28; 29; 30]. This is because the wall and reinforcement are connected by a welded type in the 1L section. The reinforcement with high specifications of 0.3 m and 1.75 m is sufficient for displacement resistance, which is the best performance in the lower area from the middle of the wall. In the case of the 1R section with the same vertical spacing of 0.3 m, the length of the reinforcement is installed as low as 1.5 m; therefore, it was determined that the shape of the 1L section exhibits a convex shape because it could not support the lower part of the wall. The 1R section, which has a reinforcement lower than 1L, at 1.5 m, and a weaker wall-reinforcement connection as the hinge type, exhibits an outwardly convex wall shape despite the same vertical spacing of 0.3 m.  
Figure 14: Load-horizontal displacement of wall curve (at the top).