## 3 Results
### Excess Pore Water Pressures  
It should be noted that the results in Figures 14 and 15 are from surface accelerations, and hence do not fully describe the behavior of the soil. Therefore, analyzing data from the pore pressure gauges could help in understanding the liquefaction mechanism of the scale model. Data readings from the pore pressure gauges are shown in Figure 19. As shown, the pore pressure rise was negligible at \(t\) = 0-190 s. However, as the soil outside the zone of the embankment started to liquefy, as indicated in Figure 17b, water seeped into the partially saturated embankment, which caused the sudden increase in the excess pore pressures. In addition, it can be seen in Figure 19 that the rise in pore pressure at PP-D reached peak values earlier than at PP-B. This might be due to inclusion of the less permeable woven polyester geotextile below the shallow foundation at location D, which resulted in the decrease of the system's ability to dissipate water. Hence, materials like  
Figure 16: Photo of shallow foundations (**a**) before shaking and (**b**) after shaking.  
geogrids and others with better drainage are suggested to reduce the effects on the pore pressure rise. Although higher excess pore water pressures were experienced earlier at location D, the shallow foundation at location D sustained slightly lesser damage, which could be mainly due to the effect of the geotextile and soil improvement. Further studies regarding the cost-effectiveness and advantages of geosynthetics are recommended. In the papers by [PERSON] et al. [45] and [PERSON] and [PERSON] [46], they concluded that geosynthetic reinforcement slightly helped against liquefaction. However, severe damage was still observed in their experiments. In the paper by [PERSON] and [PERSON] [46], the settlement of the embankment with gravel mat and geogrid was only reduced by 5 cm compared to an embankment with gravel mat only, which settled 31 cm into the ground.  
Figure 17: Variation of horizontal elastic response spectra: (**a**) \(t\) = 0–150 s, (**b**) \(t\) = 150–200 s, and (**c**) \(t\) = 200–225 s.  
Figure 18: Variation of vertical elastic response spectra: (**a**) \(t\) = 0–150 s, (**b**) \(t\) = 150–200 s, and (**c**) \(t\) = 200–225.  
The model in this study liquefied, and the geotextile tubes and shallow foundations settled into the ground. Due to extreme weakening of the soil and geotextile tube displacement, the entire embankment settled by about 5 cm and caused the soil outside of the embankment to increase by a height of 5 cm, as shown in Figure 20. Hence, after the experiment, the soil was almost level at a height of 50 cm. An experiment conducted on a dry embankment was also performed by the authors. If the embankment was not partially saturated before shaking, the embankment would not have liquefied excessively, and the shallow foundations would not have settled tremendously. The distinct damage would have been cracks and severe inertia-induced damage to the shallow foundations would have occurred, depending on the intensity of the earthquake, as shown in Figure 21. The cracking phenomenon was also observed in the experiment conducted by [PERSON] and [PERSON] [7]. In the experiment on the dry embankment, the geotextile tubes were also laterally displaced, and sunk into the weakened foundation soil.  
Figure 21: Damage sustained by the embankment if it is composed of dry silty sand.  
Figure 19: Variation of excess pore water pressure at various locations: (**a**) location A, (**b**) location B, and (**c**) location D.  
Figure 20: Photo of the scale model before and after the occurrence of lateral spreading and geotextile tube settlement: (**a**) \(t=0\) and (**b**) \(t=225\) s.