## 3 Results and Discussion
### Test on the Durability of Stabilized Soft Soil
#### 3.3.2 Seawater Erosion Resistance Test  
The seawater erosion resistance of stabilized soft soil refers to its ability to maintain strength without significant decline under seawater immersion after curing to a certain age. In coastal construction, the tidal effect often causes seawater to invade the soft soil foundation, and the salt content in the underground flow can be high. Prolonged exposure to seawater erosion may lead to problems such as cracking, which seriously affects durability.  
Artificial seawater, prepared using sea crystals, was used in the test. Samples cured for 28 days were immersed in seawater to test the change in compressive strength. The ratio of the compressive strength of the sample after immersion to the compressive strength of the 28-day reference sample was used to determine the water resistance coefficient. Figure 8 shows the curve of compressive strength for cement GC and stabilized soils G4 and G7 over seawater soaking time, and Table 7 presents the seawater erosion resistance coefficient of the stabilized soft soil. The test used stabilized soft soil mixed with seawater, with a water content of 65% and a content ratio of 20%.  
Figure 8: Curve of compressive strength of stabilized soft soil with seawater soaking time.  
Figure 7: The samples soaked for 60 days (GC, G4, and G7 from left to right).  
It can be seen from Figure 8 that as the soaking days in seawater increased, the compressive strength of cement soil GC and stabilized soils G4 and G7 gradually decreased. However, the seawater erosion resistance of stabilized soil was better than that of cement soil.  
After 14 days of seawater immersion, the compressive strengths of GC, G4, and G7 were 3.37 MPa, 6.50 MPa, and 7.17 MPa, respectively, with seawater erosion resistance coefficients of 87.39%, 92.47%, and 95.34%. After soaking for 28 days, the compressive strengths of GC, G4, and G7 decreased to 3.35 MPa, 6.47 MPa, and 7.13 MPa, respectively. After 60 days of soaking, the compressive strength of GC significantly decreased, while that of G4 and G7 remained relatively high, at 2.58 MPa, 6.36 MPa, and 6.87 MPa, respectively. The seawater erosion resistance coefficients for these samples were 66.97%, 90.48%, and 91.41%, respectively, with G7 exhibiting the best seawater erosion resistance.  
As shown in Figure 9, the cement soil sample was more severely damaged by seawater erosion. A unique white substance appeared on the surface of the cement soil sample, accompanied by multiple cracks that grew rapidly with increasing seawater soaking time. In contrast, the stabilized soil samples G4 and G7 remained intact throughout, with no visible abnormalities on their surfaces. These observations are consistent with the compressive strength test results, demonstrating that stabilized soil has better resistance to seawater erosion.  
This is primarily due to the large amount of SO4\({}^{2-}\) in seawater continuously entering the soil and absorbing a significant amount of water. Soluble salt crystals precipitate out, causing the soil to expand and leading to cracks in the GC [21]. The GGBS in the SWC has a higher SO4\({}^{2-}\) binding capacity, and the hydrated calcium aluminate formed during hydration reacts with SO4\({}^{2-}\) in seawater to produce Kuzel salt. This reaction reduces the soluble salt content and mitigates the erosive effects of seawater [22].