## 5 Results and Discussion
### Box Model Test Results  
#### 5.3.1 Load-Settlement Curves of the Four Box Model Test Cases (Clay vs Sand)  
The present study conducted the bearing capacity test with dense sand to serve as a basis for comparison with both unreinforced NMC clay and reinforced NMC clay. Here, Figure 16 shows the settlement, with the corresponding load applied at the loading plate. The unreinforced NMC clay (Case 1) with high water content (35%) showed a low bearing capacity and large deformation. Case 1 also showed a lower bearing capacity than that of dense sand (Case 2), and the results showed that dense sand (Case 2) has a higher bearing capacity than NMC clay reinforced with crushed gravel only (Case 3) by a small margin. This implies that crushed gravel is not enough as the lone reinforcement for NMC clay relative to dense sand. Thus, composite geotextiles (three layers) were added to the gravel-reinforced NMC clay (Case 4). Then, the graph showed that the Case 4 exhibited a higher bearing capacity than dense sand (Case 2) by 60% and 33% at 0.10 and 0.17\(B\), respectively. It can also be observed that Case 4 exhibited an arching curve, which slowly decayed after 0.1\(B\), while Case 2 exhibited an increasing linear bearing capacity trend. At the beginning of the loading, the difference between Case 4 and Case 2 was increasing. However, after 30 mm (0.1\(B\)) settlement, the difference decreased; it could then be expected that the two cases would have the same bearing capacity when the vertical displacement further increased. Figure 17 shows the BCR relationships of the dense sand and reinforced NMC clay over the unreinforced NMC clay in the box model test. Dense sand (Case 2) exhibited a higher BCR than gravel-reinforced NMC clay (Case 3). However, the NMC clay was reinforced with both crushed gravel and composite geotextiles (Case 4) exhibited a higher BCR than dense sand (Case 2). Figure 16: The bearing capacity analysis on box model test results. Similarly, Figure 18 shows the specific comparison of reinforced NMC clay against the dense sand and also the specific comparison of reinforced NMC clay and dense sand against the unreinforced NMC clay. The BCR beyond 1.0 implies higher bearing capacity, while a BCR of less than 1.0 implies a lower bearing capacity, with respect to its dividend. Here, the effect of crushed gravel as the top layer can be seen at 0.03\(B\), wherein both Case 3 and Case 4 showed a higher BCR than Case 2 (see Figure 18a). It is also noticeable that Case 4 has approximately 1.5 times greater BCR than Case 2 while Case 3 shows lower BCR than Case 2 after \(S=15\) mm. This clearly implies that NMC clay reinforced with crushed gravel and composite geotextiles is stronger than dense sand. Additionally, Figure 18b shows that Case 4 has a greater BCR than Case 2 after being compared to Case 1. Here, Case 2 is compared with Case 1 to show that dense sand (Case 2) has a higher BCR than unreinforced NMC clay (Case 1). However, with gravel and composite geotextile reinforcements (Case 4), the NMC clay BCR has improved and has a higher BCR than dense sand (Case 2). Figure 17: The BCR of unreinforced NMC clay versus other cases. Figure 18: The comparison of BCR for (**a**) reinforced NMC clay against the dense sand and (**b**) reinforced NMC clay and dense sand against the unreinforced NMC clay. Overall, Case 4 exhibited favorable bearing capacity, which could be desirable for field application. It can be inferred than NMC clay reinforced with crushed gravel increased the bearing capacity to be higher than unreinforced NMC clay, and adding composite geotextiles increased the bearing capacity to be higher than dense sand. It can also be inferred that the parametric strength of crushed gravel and composite geotextiles may have attributed to the increase in the soft clay's bearing capacity. The lone soft clay is weak and has poor engineering properties; thus, it may not be suitable as an embankment material.