Mechanical properties and micromechanisms of natural fiber-modified saline soil

This study explores the mechanical properties and micromechanisms of sulfuric saline soil from Kashi, Xinjiang, modified using various types and contents of eco-friendly or recycled natural fibers. The unconfined compressive strength (UCS), shear strength, and micromorphology of fiber-reinforced soils were systematically analyzed through experimental methods, including unconfined compression tests, scanning electron microscopy (SEM), and nuclear magnetic resonance (NMR). Results demonstrated that incorporating natural fibers significantly enhanced the soil's mechanical performance. For instance, UCS increased by 2.11 times with 6% rice husk fiber and by 2.8 times with 4% jute fiber (40 mm length) compared to ST. Similarly, 15 mm sisal fiber at 2% content improved UCS by 2.48 times, while palm fiber (1.5%, 20-40 mm) enhanced UCS by 2.13-2.29 times. Optimum moisture content (OMC) and maximum dry density (MDD) varied depending on fiber type and content, with the highest MDD (1.97 × 10³ kg/m³) observed at 0.6% coconut shell fiber content. Wet-dry cycle tests revealed that fiber reinforcement effectively reduced strength loss, and dissolution coefficient analysis confirmed improved resistance to saline soil degradation. These findings highlight the potential of natural fibers as a sustainable and environmentally friendly solution for stabilizing saline soils in arid regions, offering improved durability and reduced ecological impact.