Shear strength and dynamic deformation characteristics of clay stabilised with lime and lignin

This study evaluated lime-lignin composite stabilisers for clay enhancement. Results showed their synergistic effect significantly improved shear strength (S), cohesion (c), friction angle (φ), and maximum dynamic shear modulus (Gmax) of clay. Microstructural analysis revealed lime-induced granular crystals and lignin-generated cementitious products, enhancing soil structure. After 1 and 7 days curing, the clay stabilised with 6% lime and 2% lignin exhibited the highest S, c, φ and Gmax. After 14 days curing, the clay stabilised with 4% lime and 4% lignin exhibited the highest S, c, φ, and Gmax. A novel relative structural characterization method based on c and φ was proposed, alongside a modified Hardin’s model integrating relative structural to predict Gmax. The study demonstrates that 6% lime + 2% lignin and 4% lime + 4% lignin ratios effectively enhance embankment clay properties, offering sustainable solutions for industrial byproduct utilization and soil stabilisation in geotechnical engineering.