Infiltration and Strength Characteristics of Peat Soil Modified by Octadecyl Primary Amine

Peat soil presents significant engineering challenges due to its high water content, substantial organic matter, and low bearing capacity. To date, research on effective modification methods for peat soil remains limited. This study investigates the potential of octadecyl primary amine (ODA) as an amendment to enhance the hydrophobicity, water loss characteristics, and mechanical properties of peat soil. A series of tests, including water drop infiltration, wetting-drying cracking, and strength assessments, were conducted to systematically evaluate the effects of ODA on these properties. Results indicate that ODA significantly improves the hydrophobicity of peat soil, with optimal performance achieved at a concentration of 0.3%. Wetting-drying tests revealed steeper drying curves and reduced residual moisture content, with evaporation occurring in three distinct stages. Crack analysis demonstrated a denser, shorter, and narrower crack network, reflecting microstructural optimization induced by ODA. Strength tests further confirmed enhanced compressive strength, cohesion, and internal friction angle, with mechanical improvements increasing at a diminishing rate as ODA concentration rises. The underlying mechanisms of modification involve chemical interactions, microstructural reorganization, and strengthened inter-particle bonding. This research provides valuable technical insights and theoretical foundations for practical engineering applications in peat soil regions, such as road construction and foundation stabilization.