## 2 Materials and Methods  
### Experiment on the Effect of Composite Dust Suppressant on Soil Strength  
To investigate the impact of applying dust suppressants on soil strength at construction sites, a series of tests will be conducted on soil treated with a composite dust suppressant. Due to the high viscosity of the composite dust suppressant, it needs to be diluted to a certain ratio before application. This not only reduces its viscosity but also lowers its usage cost. The soil samples were randomly collected from an area near the laboratory (GPS coordinates: longitude 103.947159, latitude 30.775640) and were classified as gray paddy soil. The pH ranged from 6.5 to 7.0, indicating neutral to slightly acidic conditions. The dust suppressant itself has a neutral pH (-7.0), ensuring no significant chemical reactions with the soil. The organic matter content is less than 2 g/kg, and the soil is generally neutral to slightly acidic, nutrient-rich, and highly porous, exhibiting good infiltration capacity. These soil characteristics may enhance the observable effects of the dust suppressant in the experiments, providing clearer insights into its impact at different concentrations and treatment durations. Such conditions contribute to the accuracy and reliability of the experimental data. Insufficient dilution fails to adequately decrease the viscosity, while excessive dilution adversely affects the soil's compressive and shear resistance. Therefore, an optimal dilution ratio is crucial for enhancing the overall effectiveness of the composite dust suppressant.  
Experiment on the Effect of Composite Dust Suppressant Concentration and Curing Time on the Bearing Capacity of Stabilized Soil  
Following the Chinese Standard for unconfined compressive strength testing of soil [22], composite dust suppressant will be uniformly sprayed onto the surface of soil samples at three different concentrations: undiluted (the optimal concentration determined through laboratory testing), 10-times diluted, and 20-times diluted. After the solvent has fully penetrated, the soil samples will be shaped into uniform cylindrical molds. Each test was performed in triplicate (n = 3) to ensure result accuracy and reliability. To clarify, in the experiment evaluating the effect of composite dust suppressant concentration on the bearing capacity of solidified soil, the compressive strength was measured after a 7-day curing period under natural conditions. By this time, the suppressant had already formed a film, and all water had evaporated, ensuring that there was no difference in water application among treatments. A control group treated only with pure water was included to evaluate the effect of the dust suppressant. Since completely dry soil could not form a stable mold for testing, the pure water group served as a baseline, and after seven days of curing, the water had fully evaporated, effectively functioning as a non-suppressant control. The total spray volume was 250 mL, with an individual droplet size of 0.1 L/m\({}^{2}\), ensuring even distribution across the sample surface. A cylindrical mold was created after evenly spraying the soil sample with the composite dust suppressant diluted tenfold, allowing full penetration of the solvent. The cylindrical molds were cured at room temperature for 7, 14, and 28 days, respectively. An unconfined compression test was performed on the cured samples using a fully automatic triaxial apparatus, with a loading plate speed of 2 mm/min, to determine their compressive strengths. Their compressive strength will be measured after curing for 7 days in a natural environment to determine the optimal dilution ratio for the composite dust suppressant. The specific experimental groups are outlined in Table 1.