Transforming mine dump waste soil into biogeo-composites with vegetation growth regulation function through bio-mediated treatment.

Valorization of mine waste soils into sustainable materials provides both ecological protection and recycling benefits. This study develops a calcium lignosulfonate (CLS)-enzyme-induced calcium carbonate precipitation (EICP)-driven biogeo-composite that simultaneously enhances mechanical stability, regulates hydraulic behavior, and promotes vegetation growth. Laboratory tests demonstrated that CLS-EICP treatment increased shear strength of soils through cohesion enhancement driven by rigid CaCO₃ bonding and ductile CLS bridging. Hydraulic conductivity reduced by two orders of magnitude and slaking resistance significantly enhanced. Microstructural analyses confirmed a dense organic-inorganic hybrid network formation, enabling a transition from surface to volumetric cementation and promoting structural densification. Field trials further validated these findings, as biogeo-composite-treated slopes resisted gully erosion, delayed pore water pressure build-up, and maintained overall stability while supporting uniform vegetation growth. These results highlight the dual role of CLS-EICP composites in slope reinforcement and eco-functional regulation, offering a scalable pathway for the valorization of waste soils.