Abstract: The utilization of humus soil is a crucial factor influencing the feasibility and cost-effectiveness of landfill excavation. Solidification/stabilization technology holds promising engineering applications for humus soil treatment. In this study, four types of curing agents including ordinary Portland cement (OPC), sulphoaluminate cement (SAC), cement-slag mixture (OG), and magnesium oxide-slag binder (MG), were chosen for a systematic investigation of the evolution of engineering properties, permeability, leaching characteristics, and durability of solidified humus soils. The results indicate a significant enhancement in compressive strength of solidified humus soils, with SAC treatment exhibiting the highest compressive strength at 10% and 15% dosages, while OPC and OG solidified humus soils show higher strength at 20%. Additionally, the strength development of MG solidified soils is lower compared to other solidified soils. Increasing the dosage of curing agents can effectively counteract the inhibitory effect of organic matter in soil, with 15% being an appropriate dosage for both engineering and economic considerations. At a 15% dosage, solidified humus soil can meet the regulatory limit for Class IV water quality, except for OPC treatment, which is ineffective for As immobilization. Regarding durability, OG solidified humus soil exhibits the highest resistance to dry-wet and freeze-thaw cycles, while SAC solidified soil shows the weakest resistance to dry-wet cycles but superior frost resistance performance to OPC. Consequently, solidified humus soils can serve as filling materials in landfills and subbase materials in road engineering, offering theoretical and parameter support for the resource utilization of humus soils in landfills.

Key words: humus soil, solidification/stabilization(S/S), engineering properties, environmental properties, durability