## 4 Results and Discussion
### Effect of Exavation Pit Dimensions on PSR  
Excavation geometry and soil parameters were taken from the Tepe Shopping Mall case. In the investigation of the excavation pit dimensions, the slope angle (\(\beta\)) was accepted as zero, the nail length was taken as half of the excavation depth, and the effect of the change in the excavation dimensions (B and L) on the plane-strain ratio (PSR) behavior was examined. The excavation pit dimensions consisted of the primary wall length (L) and secondary wall length (B). The model boundary conditions were taken as three times the excavation widths, and attention was paid to the boundary conditions. The model depth was taken as six times the excavation depth (Figure 8). Excavation pit parametric dimensions were determined as multiples of the excavation depth (H). To investigate the dimensions of the excavation pit, 25 Plaxis 3D models and 25 Plaxis 3D plane-strain models were created and analyzed (Table 4). In the analysis studies, it was seen that different B conditions had no effect on plane-strain ratio (PSR) changes under the same primary wall length (L) length conditions. Under the same secondary wall length (B) conditions, the PSR value remained at low values, at most approximately 0.65, in the L length 2H condition. Under the same B conditions,  
Figure 7: General flowchart of research on the relationship between PSR and parametric factors. Effects of Slope Angle (\(\beta\)), Wall Angle (\(\alpha\)), Exavation Depth (H), Nail Length (L/H), and Distance from Corner (xH) on PSR  
There are many controversial studies on the corner effect of shoring structure type, soil type, and excavation pit dimensions [3, 27, 53, 55]. There are limited studies on how variables such as the back slope angle (\(\beta\)), nailed wall angle (\(\alpha\)), nail length (L/H), and excavation depth (H) affect the corner effect in nailed walls. At this stage of the study, the effects of the specified factors on the plane-strain ratio (PSR) were investigated. The nail length was kept constant throughout the depth. The width of the slope angle was determined as two times the width of the excavation depth (2H), since the displacement increase rate did not change significantly after 2H distance. A total of 336 3D models and 336 plane-strain slice models were created using the parametric variables shown in Figure 10, and displacement analysis studies were carried out. In Plaxis 3D models, the primary wall (L) and secondary wall (B) distances of the excavation pit are kept equal (B = L). This is because the length of the secondary wall (B) has no effect on the primary wall (L) displacements (Figure 9). Additionally, no significant change in the plane-strain ratio (PSR) was observed after 3H distance. Therefore, B = L = 6H excavation dimensions were chosen in all Plaxis 3D models (Figure 11a). Since the lateral distance between the nails was 1.5 m in this case, the width was kept constant at 1.5 m in all 3D and plane-strain slice models (Figure 11b). While creating models in analysis studies, dimensions were determined by taking boundary conditions into account (Figure 11). Figure 11: Finite element model for the reference for the calculation of the PSR: (**a**) 3D model; (**b**) 3D plane-strain slice model. Figure 10: Parametric variables and properties based on Plaxis 2D and Plaxis 3D models. A total of 336 3D models and 336 plane-strain slice models were analyzed for corner effect research based on five variable conditions on nailed walls. The change in plane-strain ratio (PSR) values was calculated for each excavation depth at distances from the corner of 0, 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 times the excavation depth, and graphs were created. During the plane-strain slice model analyses, 106 models collapsed, and during the 3D model displacement analyses, 89 models collapsed. The PSR values based on the non-collapse lateral displacement analysis results are presented in Figure 12, with a total number of 1610 data points.