## 5 Results  
Comparative Analysis of Seismic Subsidence Based on Elastic-Plastic Dynamic True-Coupled Consolidation  
In the later period of the earthquake, the subsidence distribution of the natural foundation, foundation reinforced with isometric gravel piles, and foundation reinforced with subarea long-short gravel piles are as shown in Figure 8a-c, respectively. In natural foundation, the earthquake resulted in an uplift of 0.20 m in surface sand near both sides of the embankment; this was accompanied with a seismic subsidence of 0.30 m in the midsection of the roadbed. In the foundation reinforced with isometric gravel piles, there was no obvious deformation of the soil on either side of the roadbed; however, the seismic subsidence in the midsection of the roadbed was sharply reduced to 0.04 m. Meanwhile, in the foundation reinforced with subarea long-short gravel piles, the seismic subsidence in the midsection of the roadbed was sharply reduced to 0.045 m.  
Figure 8: Contours of seismic subsidence of natural foundation and reinforced foundations. (**a**) Natural foundation. (**b**) Foundation reinforced with isometric gravel piles. (**c**) Foundation reinforced with subarea long-short gravel piles. Compared with the natural foundation, the seismic subsidence of the foundation reinforced with isometric gravel piles was reduced by 86%, and that of the foundation reinforced with subarea long-short gravel piles was reduced by 85%. In the two reinforcement schemes, the uplift problem observed in the surface soil on both sides of the roadbed was basically eliminated. The reduction in seismic subsidence was remarkable, and both reinforcement schemes could effectively control the seismic subsidence. However, it is worth noting that the pile consumption of isometric gravel piles scheme is obviously greater than that of subarea long-short gravel piles scheme. Comparative Analysis of Pore Pressure during Earthquake Based on Elastic-Plastic Dynamic True-Coupled Consolidation  
Twenty seconds into an earthquake, the dynamic excess pore water pressure distribution in natural foundation, foundation reinforced with isometric gravel piles, and foundation reinforced with subarea long-short gravel piles in the deeply deposited saturated liquefiable soil are shown in Figure 9a-c, respectively. Figure 9: Cont. In natural foundation, the dynamic excess pore pressure in saturated sand increased significantly during the earthquake; moreover, the maximum pore pressure reached about 88.0 kPa at a depth of 8.0 m in the midsection of the roadbed. Thus, the potential for liquefaction increased greatly. In the foundation reinforced with isometric gravel piles, the dynamic excess pore pressure, at a depth of 5.0 m in the midsection of the roadbed, was sharply reduced to 4.0 kPa; meanwhile, in the foundation reinforced with subarea long-short gravel piles, the dynamic excess pore pressure at the same position was sharply reduced to 5.0 kPa. Compared with the natural foundation, the dynamic excess pore pressure in the foundation reinforced with isometric gravel piles was reduced by 95%, and the foundation reinforced with subarea long-short gravel piles was reduced by 94%. The reduction in dynamic excess pore pressure was remarkable in both reinforcement schemes. Both reinforcement schemes could effectively control the dynamic excess pore pressure during the earthquake, and thus, the liquefaction in the stratigraphic environment of saturated sand could be greatly reduced. However, it is still worth noting that the pile consumption of the isometric gravel piles scheme is obviously greater than that of the subarea long-short gravel piles scheme. Comparative Analysis of Time Histories of Dynamic Pore Pressure Based on Elastic-Plastic Dynamic True-Coupled Consolidation  
In order to analyze the time histories of dynamic excess pore water pressure, two observation points, P1 and P2, were selected at depths of 3.0 m and 8.0 m, respectively, below the left edge of the embankment.