## 3 Results and Discussion
### Mechanical Performance of Eco-Soil  
The influence of hydrogel soil curing agent dosage on the unconfined compressive strength (UCS) of eco-soil was investigated across different curing ages, with results shown in Figure 6. The horizontal axis in the figure represents the mass ratio of the active ingredients in the hydrogel to the ecological soil. As depicted in Figure 6, under constant moisture content (40 wt.%) and identical curing conditions, the dosage of active ingredients exhibited a significantly positive correlation with the UCS of eco-soil. When the active ingredients increased from 0% to 2.0%, the 7 d UCS of eco-soil surged from 0.13 MPa to 1.55 MPa, representing a 1092% enhancement. According to the CJJ/T 286-2018 standard [25], this meets the 7 d strength requirement for Grade III stabilized soil.  
Further analysis reveals that the hydrogel curing agent system exhibits unique time-dependent properties. At the optimal dosage of 2.0%, the 28 d strength reached 1.62 MPa, representing only a 4.52% increase over the 7 d baseline value. This enhancement is significantly lower than that of traditional Portland-based curing agents (conventional improvement > 30%). The limited late-stage strength gain may be attributed to the primary efficacy of the hydrogel curing agent occurring during the early curing phase, particularly within the first 48 h. Based on strength development trends, over 90% of the crosslinking reactions in the hydrogel system are completed within 7 d. Its rapid three-dimensional network formation mechanism effectively mitigates the risk of shrinkage-induced cracking observed in traditional materials during later stages. In practical applications, this property accelerates project timelines, reduces labor costs, and enhances quality controllability. Specifically, in scenarios such as ecological slope protection--where both mechanical performance and vegetation growth must be balanced--the controllable strength development curve can precisely align with plant root growth rates, avoiding the ecological isolation effect caused by conventional high-strength stabilized soils. Considering the need for stabilized soils to accommodate root proliferation, hydrogel soil curing agents prioritize ecological compatibility over mechanical performance metrics compared to traditional agents. Consequently, lower dosages may be selected while still meeting project requirements.  
Figure 7 illustrates the influence of heating duration on the unconfined compressive strength (UCS) of eco-soil containing hydrogel curing agents, with an active ingredients dosage of 2.0 wt.%. As shown in Figure 7, the UCS of eco-soil increased with prolonged heating time. When the heating duration rose from 0 h to 2 h, the 7 d UCS of encapsulated specimens surged from an initial value of 0.13 MPa to 1.23 MPa, achieving 79% of the  
Figure 6: Effect of active ingredients in hydrogel on UCS of eco-soil.  
unencapsulated control group's strength (1.55 MPa), with a strength loss rate confined within 21%. This demonstrates that external thermal stimulation positively regulates stabilized soil specimens, confirming the feasibility of precisely releasing hydrogel initiators via temperature modulation. Notably, extending heating time to 3 h resulted in a marginal strength increase to 1.25 MPa, showing reduced efficacy compared to the 2 h treatment. Considering energy efficiency ratios and material stability, optimal thermal input power must be selected. This ensures that the thermo-responsive eco-soil system maintains high strength conversion efficiency while avoiding matrix damage caused by excessive heat exposure.