Acid sulfate soils (ASSs) are naturally formed soils or sediments that are produced under waterlogged and poorly drained conditions. The sulfides can move to the surface water and into subsurface water and cause loss of nutrients in the soil and destroy the soil structure. To perform effective management of the ASSs located above and under the groundwater table, the unsaturated characteristics of ASSs before and after neutralization treatments should be investigated. An ASS was sampled from the natural soil layer around Ilkwang mine in Busan, South Korea, and CaCO₃, which is a neutralizer, and polyacrylamide (PAM) which is a soil stabilizer, were mixed with the ASS in the neutralization treatment. The soil-water characteristics curves (SWCCs) and hydraulic conductivity functions (HCFs) of the drying-wetting processes of the ASS before and after the neutralization treatment were measured and assessed using the van Genuchten model. According to the assessment results of the SWCCs and HCFs, the matric suction of the ASS after the treatment was smaller than that before the treatment at the same volumetric water content (VWC). Additionally, the hydraulic conductivity of the ASS after treatment was larger than that before treatment at the same effective degree of saturation because the effective particle size of the ASS increased and the pore size among particles increased due to soil aggregation. It was confirmed that the neutralization treatment improved the hydrological properties of the ASS and the ASS after treatment may be utilized as sound materials for various fields.

酸性硫酸盐土壤（ASSs）是自然形成的土壤或沉积物，是在涝渍和排水不良的条件下产生的。硫化物可移至地表水并进入地下水，并导致土壤养分流失，破坏土壤结构。为了对位于地下水位上方和下方的ASS进行有效管理，应研究中和处理前后ASS的不饱和特性。ASS是从韩国釜山Ilkwang矿周围的天然土壤层和CaCO ₃取样的在中和处理中，将作为中和剂的，和作为土壤稳定剂的聚丙烯酰胺（PAM）与ASS混合。使用van Genuchten模型测量和评估中和处理前后ASS的干湿过程的土壤-水特征曲线（SWCC）和水力传导函数（HCF）。根据SWCC和HCF的评估结果，在相同体积水含量（VWC）下，处理后ASS的基质吸力要小于处理前的ASS。另外，在相同的有效饱和度下，处理后的ASS的水力传导率大于处理前的水力传导率，这是因为由于土壤的聚集，ASS的有效粒径增加并且颗粒之间的孔径增大。